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Chaves FM, Wasinski F, Tavares MR, Mansano NS, Frazao R, Gusmao DO, Quaresma PGF, Pedroso JAB, Elias CF, List EO, Kopchick JJ, Szawka RE, Donato J. Effects of the Isolated and Combined Ablation of Growth Hormone and IGF-1 Receptors in Somatostatin Neurons. Endocrinology 2022; 163:6565600. [PMID: 35395079 PMCID: PMC9070500 DOI: 10.1210/endocr/bqac045] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Indexed: 11/19/2022]
Abstract
Hypophysiotropic somatostatin (SST) neurons in the periventricular hypothalamic area express growth hormone (GH) receptor (GHR) and are frequently considered as the key neuronal population that mediates the negative feedback loop controlling the hypothalamic-GH axis. Additionally, insulin-like growth factor-1 (IGF-1) may also act at the hypothalamic level to control pituitary GH secretion via long-loop negative feedback. However, to the best of our knowledge, no study so far has tested whether GHR or IGF-1 receptor (IGF1R) signaling specifically in SST neurons is required for the homeostatic control of GH secretion. Here we show that GHR ablation in SST neurons did not impact the negative feedback mechanisms that control pulsatile GH secretion or body growth in male and female mice. The sex difference in hepatic gene expression profile was only mildly affected by GHR ablation in SST neurons. Similarly, IGF1R ablation in SST neurons did not affect pulsatile GH secretion, body growth, or hepatic gene expression. In contrast, simultaneous ablation of both GHR and IGF1R in SST-expressing cells increased mean GH levels and pulse amplitude in male and female mice, and partially disrupted the sex differences in hepatic gene expression. Despite the increased GH secretion in double knockout mice, no alterations in body growth and serum or liver IGF-1 levels were observed. In summary, GHR and IGF1R signaling in SST neurons play a redundant role in the control of GH secretion. Furthermore, our results reveal the importance of GH/IGF-1 negative feedback mechanisms on SST neurons for the establishment of sex differences in hepatic gene expression profile.
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Affiliation(s)
- Fernanda M Chaves
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - Frederick Wasinski
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - Mariana R Tavares
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - Naira S Mansano
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, 05508-900, Brazil
| | - Renata Frazao
- Departamento de Anatomia, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, 05508-900, Brazil
| | - Daniela O Gusmao
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - Paula G F Quaresma
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - João A B Pedroso
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
| | - Carol F Elias
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109-5622, USA
| | - Edward O List
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701USA
| | - John J Kopchick
- Edison Biotechnology Institute and Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, 45701USA
| | - Raphael E Szawka
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, 31270-901, Brazil
| | - Jose Donato
- Departamento de Fisiologia e Biofisica, Instituto de Ciencias Biomedicas, Universidade de Sao Paulo, Sao Paulo, SP, 05508-000, Brazil
- Correspondence: Jose Donato Jr, PhD, Av. Prof. Lineu Prestes, 1524, São Paulo, SP, 05508000, Brazil.
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Herrera-Martínez Y, Alzas Teomiro C, León Idougourram S, Molina Puertas MJ, Calañas Continente A, Serrano Blanch R, Castaño JP, Gálvez Moreno MÁ, Gahete MD, Luque RM, Herrera-Martínez AD. Sarcopenia and Ghrelin System in the Clinical Outcome and Prognosis of Gastroenteropancreatic Neuroendocrine Neoplasms. Cancers (Basel) 2021; 14:cancers14010111. [PMID: 35008278 PMCID: PMC8750458 DOI: 10.3390/cancers14010111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 12/13/2022] Open
Abstract
Simple Summary Malnutrition and sarcopenia affect clinical outcomes in cancer patients. Nutritional evaluation in patients with neuroendocrine neoplasms (NENs) is not routinely performed. Currently, the evaluation of sarcopenia using CT scans is the gold standard in cancer patients, additionally, anthropometric, biochemical and molecular analysis of patients with gastroenteropancreatic NENs at diagnosis was perfomed. The expression levels of key ghrelin system components were assessed in 63 tumor samples. Results: Nutritional parameters were similar in GEP-NEN tumors of different origin. Relapsed disease was associated with decreased BMI. Patients who presented with weight loss at diagnosis had significantly lower overall survival (108 (25–302) vs. 263 (79–136) months). Ghrelin O-acyltransferase (GOAT) enzyme expression was higher in these patients. The prevalence of sarcopenia using CT images reached 87.2%. Mortality was observed only in patients with sarcopenia. Muscle evaluation was correlated with biochemical parameters but not with the expression of ghrelin system components. Conclusion: Survival is related to the nutritional status of patients with GEP-NENs and also to the molecular expression of some relevant ghrelin system components. Routine nutritional evaluation should be performed in these patients, in order to prescribe appropriate nutritional support, when necessary, for increasing quality of life and improving clinical outcomes. Abstract Background: Malnutrition and sarcopenia affect clinical outcomes and treatment response in cancer patients. Patients with neuroendocrine neoplasms (NENs) may present with additional symptoms related to tumor localization in the gastrointestinal tract and hormone secretion, increasing the risk and effects of sarcopenia. Aim: To explore the presence of malnutrition and sarcopenia in gastroenteropancreatic (GEP)-NEN patients, their relation to tumor characteristics, patient outcomes, survival and the molecular expression of ghrelin system components in the tumor. Patients and methods: One-hundred-and-four patients were included. Anthropometric, biochemical and CT-scans at diagnosis were evaluated. The expression levels of key ghrelin system components were assessed in 63 tumor samples. Results: Nutritional parameters were similar in GEP-NEN tumors of different origin. Relapsed disease was associated with decreased BMI. Patients who presented with weight loss at diagnosis had significantly lower overall survival (108 (25–302) vs. 263 (79–136) months). Ghrelin O-acyltransferase (GOAT) enzyme expression was higher in these patients. The prevalence of sarcopenia using CT images reached 87.2%. Mortality was observed only in patients with sarcopenia. Muscle evaluation was correlated with biochemical parameters but not with the expression of ghrelin system components. Conclusion: Survival is related to the nutritional status of patients with GEP-NENs and also to the molecular expression of some relevant ghrelin system components. Routine nutritional evaluation should be performed in these patients, in order to prescribe appropriate nutritional support, when necessary, for increasing quality of life and improving clinical outcomes.
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Affiliation(s)
| | - Carlos Alzas Teomiro
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - Soraya León Idougourram
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - María José Molina Puertas
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - Alfonso Calañas Continente
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - Raquel Serrano Blanch
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Medical Oncology Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - Justo P. Castaño
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, 14014 Cordova, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 14004 Cordova, Spain
| | - María Ángeles Gálvez Moreno
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
| | - Manuel D. Gahete
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, 14014 Cordova, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 14004 Cordova, Spain
| | - Raúl M. Luque
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, 14014 Cordova, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, 14004 Cordova, Spain
| | - Aura D. Herrera-Martínez
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC), Reina Sofia University Hospital, 14004 Cordova, Spain; (C.A.T.); (S.L.I.); (M.J.M.P.); (A.C.C.); (R.S.B.); (J.P.C.); (M.Á.G.M.); (M.D.G.); (R.M.L.)
- Endocrinology and Nutrition Service, Reina Sofia University Hospital, 14004 Cordova, Spain
- Correspondence:
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Effects of Astragalus Extract Mixture HT042 on Circulating IGF-1 Level and Growth Hormone Axis in Rats. CHILDREN 2021; 8:children8110975. [PMID: 34828688 PMCID: PMC8622163 DOI: 10.3390/children8110975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
Astragalus extract mixture HT042 is a standardized functional food granted by the Korean FDA for promoting “Children’s Height Growth”. In this study, we determined whether HT042 affects circulatory Insulin-like growth factor-1 (IGF-1) after administration and investigated whether Growth hormone (GH), Growth hormone-releasing hormone receptor (GHRH-R), and Growth hormone secretagogue receptor (GHS-R) mRNAs are expressed in the pituitary, and whether Growth hormone-releasing hormone (GHRH) and Somatostatin (SST) are expressed in the hypothalamus. We also evaluated the growth effect of HT042 on endochondral bone formation. Male Sprague-Dawley rats in the control and HT042 groups were orally administered a single dose of the control and HT042, respectively, and those in the recombinant human GH (rhGH) group were subcutaneously injected with rhGH. Tetracycline was injected intraperitoneally 72 h prior to sacrifice to decide endochondral bone formation. To determine the endocrine or paracrine/autocrine mechanism, we evaluated the expression of local BMP-2 and IGF-1, an immunohistochemical study after HT042 administration. It was confirmed that the growth-promoting effect of HT042 can be contributed to the increase in serum IGF-1, which can be stimulated by GH secretion. Administration of HT042 modulated the activity of GHRH-R and GHR-S in the pituitary gland and promoted GH secretion, thereby changing longitudinal growth through GH/IGF-1 mediation. Results for GHRH and SST expression demonstrated that the hypothalamus can be influenced and mediated by HT042 through a complex neuroendocrine regulatory system. In addition, it was confirmed by oral administration for 10 days that HT042 increased bone formation in cartilage, which is important for height growth. The effect of HT042 could be owing to upregulation of local Bone morphogenetic protein-2 (BMP-2) and IGF-1 expression in the growth plate, which could be regarded as a GH-dependent autocrine/paracrine pathway, as well as circulatory IGF-1.
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Gesmundo I, Granato G, Fuentes-Fayos AC, Alvarez CV, Dieguez C, Zatelli MC, Congiusta N, Banfi D, Prencipe N, Leone S, Brunetti L, Castaño JP, Luque RM, Cai R, Sha W, Ghigo E, Schally AV, Granata R. Antagonists of Growth Hormone-Releasing Hormone Inhibit the Growth of Pituitary Adenoma Cells by Hampering Oncogenic Pathways and Promoting Apoptotic Signaling. Cancers (Basel) 2021; 13:cancers13163950. [PMID: 34439107 PMCID: PMC8393969 DOI: 10.3390/cancers13163950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/26/2021] [Accepted: 08/03/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary Many studies have demonstrated that the antagonists of growth hormone-releasing hormone (GHRH) exert inhibitory activities in a variety of experimental cancers; however, their potential antitumor role in pituitary adenomas (PAs) remains largely unknown. Here, we show that GHRH antagonists of Miami (MIA) class, MIA-602 and MIA-690, are able to reduce the growth and promote cell death in hormone-secreting PA cell lines, through the inhibition of mechanisms implicated in tumorigenesis and cancer progression. MIA-602 and MIA-690 also decreased the viability of tumor cells derived from human pituitary tumors. Overall, these findings suggest that GHRH antagonists may represent new therapeutic tools for the treatment of PAs, both alone or in combination with standard pharmacological treatments. Abstract Pituitary adenomas (PAs) are intracranial tumors, often associated with excessive hormonal secretion and severe comorbidities. Some patients are resistant to medical therapies; therefore, novel treatment options are needed. Antagonists of growth hormone-releasing hormone (GHRH) exert potent anticancer effects, and early GHRH antagonists were found to inhibit GHRH-induced secretion of pituitary GH in vitro and in vivo. However, the antitumor role of GHRH antagonists in PAs is largely unknown. Here, we show that the GHRH antagonists of MIAMI class, MIA-602 and MIA-690, inhibited cell viability and growth and promoted apoptosis in GH/prolactin-secreting GH3 PA cells transfected with human GHRH receptor (GH3-GHRHR), and in adrenocorticotropic hormone ACTH-secreting AtT20 PA cells. GHRH antagonists also reduced the expression of proteins involved in tumorigenesis and cancer progression, upregulated proapoptotic molecules, and lowered GHRH receptor levels. The combination of MIA-690 with temozolomide synergistically blunted the viability of GH3-GHRHR and AtT20 cells. Moreover, MIA-690 reduced both basal and GHRH-induced secretion of GH and intracellular cAMP levels. Finally, GHRH antagonists inhibited cell viability in human primary GH- and ACTH-PA cell cultures. Overall, our results suggest that GHRH antagonists, either alone or in combination with pharmacological treatments, may be considered for further development as therapy for PAs.
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Affiliation(s)
- Iacopo Gesmundo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Giuseppina Granato
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Antonio C. Fuentes-Fayos
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Clara V. Alvarez
- Centro de Investigaciones Médicas (CIMUS) e Instituto de Investigaciones Sanitarias, University of Santiago de Compostela and Complexo Hospitalario Universitario of Santiago de Compostela, 14004 Santiago de Compostela, Spain; (C.V.A.); (C.D.)
| | - Carlos Dieguez
- Centro de Investigaciones Médicas (CIMUS) e Instituto de Investigaciones Sanitarias, University of Santiago de Compostela and Complexo Hospitalario Universitario of Santiago de Compostela, 14004 Santiago de Compostela, Spain; (C.V.A.); (C.D.)
| | - Maria Chiara Zatelli
- Section of Endocrinology and Internal Medicine, Department of Medical Sciences, University of Ferrara, 15706 Ferrara, Italy;
| | - Noemi Congiusta
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Dana Banfi
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Nunzia Prencipe
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Sheila Leone
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (S.L.); (L.B.)
| | - Luigi Brunetti
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (S.L.); (L.B.)
| | - Justo P. Castaño
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Raúl M. Luque
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Department of Cell Biology, Physiology and Immunology, University of Córdoba and Reina Sofia University Hospital, 14004 Córdoba, Spain; (A.C.F.-F.); (J.P.C.); (R.M.L.)
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 28029 Madrid, Spain
| | - Renzhi Cai
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
| | - Wei Sha
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
| | - Ezio Ghigo
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
| | - Andrew V. Schally
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (R.C.); (W.S.); (A.V.S.)
- Endocrine, Polypeptide and Cancer Institute, Veterans Affairs Medical Center, Miami, FL 33125, USA
- Comprehensive Cancer Center, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Division of Hematology/Oncology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Department of Pathology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Riccarda Granata
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Science, University of Turin, 10126 Turin, Italy; (I.G.); (G.G.); (N.C.); (D.B.); (N.P.); (E.G.)
- Correspondence:
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Omouessi ST, Leipprandt JR, Akoume MY, Charbeneau R, Wade S, Neubig RR. Mice with an RGS-insensitive Gα i2 protein show growth hormone axis dysfunction. Mol Cell Endocrinol 2021; 521:111098. [PMID: 33278490 DOI: 10.1016/j.mce.2020.111098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/22/2020] [Accepted: 11/26/2020] [Indexed: 01/03/2023]
Abstract
Mice carrying an RGS-insensitive Gαi2 mutation display growth retardation early after birth. Although the growth hormone (GH)-axis is a key endocrine modulator of postnatal growth, its functional state in these mice has not been characterized. The present study was undertaken to address this issue. Results revealed that pituitary mRNA levels for GH, prolactin (PRL), somatostatin (SST), GH-releasing-hormone receptor (GHRH-R) and GH secretagogue receptor (GHS-R) were decreased in mutants compared to controls. These changes were reflected by a significant decrease in plasma levels of GH, IGF-1 and IGF-binding protein-3 (IGFBP-3). Mutants were also less responsive to GHRH and ghrelin (GhL) on GH stimulation of release from pituitary primary cell cultures. In contrast, they were more sensitive to the inhibitory effect of SST. These data provide the first evidence for an alteration of the functional state of the GH-axis in Gαi2G184S mice that likely contributes to their growth retardation.
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MESH Headings
- Animals
- Cells, Cultured
- Female
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- Ghrelin/pharmacology
- Growth Disorders/genetics
- Growth Disorders/metabolism
- Growth Hormone/blood
- Growth Hormone/genetics
- Growth Hormone/metabolism
- Growth Hormone-Releasing Hormone/blood
- Growth Hormone-Releasing Hormone/genetics
- Growth Hormone-Releasing Hormone/pharmacology
- Insulin-Like Growth Factor Binding Protein 3/blood
- Insulin-Like Growth Factor Binding Protein 3/genetics
- Insulin-Like Growth Factor I/genetics
- Insulin-Like Growth Factor I/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- Prolactin/genetics
- Prolactin/metabolism
- RGS Proteins/genetics
- RGS Proteins/metabolism
- Real-Time Polymerase Chain Reaction
- Receptors, Ghrelin/metabolism
- Receptors, Neuropeptide/genetics
- Receptors, Neuropeptide/metabolism
- Receptors, Pituitary Hormone-Regulating Hormone/genetics
- Receptors, Pituitary Hormone-Regulating Hormone/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Somatostatin/genetics
- Somatostatin/metabolism
- Somatostatin/pharmacology
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Affiliation(s)
- S Thierry Omouessi
- Department of Pharmacology, University of Michigan Medical School, Michigan, USA; Department of Physiology, Faculty of Medicine, Université des Sciences de la Santé (USS) de Libreville, Libreville, Gabon.
| | - Jeffrey R Leipprandt
- Department of Pharmacology and Toxicology, Michigan State University, Michigan, USA
| | - Marie-Yvonne Akoume
- International Research Institute of Biomedical Sciences & Biotechnology-Carles Kambangoye (IRBK), Université Internationale de Libreville, Essassa, Gabon; Viscogliosi Laboratory in Molecular Genetics of Musculoskeletal Diseases, Sainte-Justine University Hospital Research Center, Montréal, Quebec, Canada
| | - Raelene Charbeneau
- Department of Pharmacology, University of Michigan Medical School, Michigan, USA
| | - Susan Wade
- Department of Pharmacology, University of Michigan Medical School, Michigan, USA
| | - Richard R Neubig
- Department of Pharmacology, University of Michigan Medical School, Michigan, USA; Department of Pharmacology and Toxicology, Michigan State University, Michigan, USA
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Miles TK, Silva Moreira AR, Allensworth-James ML, Odle AK, Haney AC, MacNicol AM, MacNicol MC, Childs GV. Sex differences in somatotrope response to fasting: biphasic responses in male mice. J Endocrinol 2020; 247:213-224. [PMID: 33112825 PMCID: PMC7673470 DOI: 10.1530/joe-20-0275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 09/22/2020] [Indexed: 11/08/2022]
Abstract
Anterior pituitary somatotropes are important metabolic sensors responding to leptin by secreting growth hormone (GH). However, reduced leptin signals caused by fasting have not always correlated with reduced serum GH. Reports show that fasting may stimulate or reduce GH secretion, depending on the species. Mechanisms underlying these distinct somatotrope responses to fasting remain unknown. To define the somatotrope response to decreased leptin signaling we examined markers of somatotrope function over different time periods of fasting. Male mice were fasted for 24 and 48 h, with female mice fasted for 24 h compared to fed controls ad libitum. Body weight and serum glucose were reduced in both males and females, but, unexpectedly, serum leptin was reduced only in males. Furthermore, in males, serum GH levels showed a biphasic response with significant reductions at 24 h followed by a significant rise at 48 h, which coincided with the rise in serum ghrelin levels. In contrast, females showed an increase in serum GH at 24 h. We then explored mechanisms underlying the differential somatotrope responses seen in males and observed that pituitary levels of Gh mRNA increased, with no distinction between acute and prolonged fasting. By contrast, the Ghrhr mRNA (encoding GH releasing hormone receptor) and the Ghsr mRNA (encoding the ghrelin receptor) were both greatly increased at prolonged fasting times coincident with increased serum GH. These findings show sex differences in the somatotrope and adipocyte responses to fasting and support an adaptive role for somatotropes in males in response to multiple metabolic signals.
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Affiliation(s)
- Tiffany K Miles
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ana Rita Silva Moreira
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Melody L Allensworth-James
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Angela K Odle
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Anessa C Haney
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Angus M MacNicol
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Melanie C MacNicol
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Gwen V Childs
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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7
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Allensworth-James ML, Odle AK, Lim J, LaGasse AN, Miles TK, Hardy LL, Haney AC, MacNicol MC, MacNicol AM, Childs GV. Metabolic signalling to somatotrophs: Transcriptional and post-transcriptional mediators. J Neuroendocrinol 2020; 32:e12883. [PMID: 32657474 PMCID: PMC8086172 DOI: 10.1111/jne.12883] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/17/2020] [Accepted: 06/10/2020] [Indexed: 12/19/2022]
Abstract
In normal individuals, pituitary somatotrophs optimise body composition by responding to metabolic signals from leptin. To identify mechanisms behind the regulation of somatotrophs by leptin, we used Cre-LoxP technology to delete leptin receptors (LEPR) selectively in somatotrophs and developed populations purified by fluorescence-activated cell sorting (FACS) that contained 99% somatotrophs. FACS-purified, Lepr-null somatotrophs showed reduced levels of growth hormone (GH), growth hormone-releasing hormone receptor (GHRHR), and Pou1f1 proteins and Gh (females) and Ghrhr (both sexes) mRNAs. Pure somatotrophs also expressed thyroid-stimulating hormone (TSH) and prolactin (PRL), both of which were reduced in pure somatotrophs lacking LEPR. This introduced five gene products that were targets of leptin. In the present study, we tested the hypothesis that leptin is both a transcriptional and a post-transcriptional regulator of these gene products. Our tests showed that Pou1f1 and/or the Janus kinase/signal transducer and activator of transcription 3 transcriptional regulatory pathways are implicated in the leptin regulation of Gh or Ghrhr mRNAs. We then focused on potential actions by candidate microRNAs (miRNAs) with consensus binding sites on the 3' UTR of Gh or Ghrhr mRNAs. Somatotroph Lepr-null deletion mutants expressed elevated levels of miRNAs including miR1197-3p (in females), miR103-3p and miR590-3p (both sexes), which bind Gh mRNA, or miRNA-325-3p (elevated in both sexes), which binds Ghrhr mRNA. This elevation indicates repression of translation in the absence of LEPR. In addition, after detecting binding sites for Musashi on Tshb and Prl 3' UTR, we determined that Musashi1 repressed translation of both mRNAs in in vitro fluc assays and that Prl mRNA was enriched in Musashi immunoprecipitation assays. Finally, we tested ghrelin actions to determine whether its nitric oxide-mediated signalling pathways would restore somatotroph functions in deletion mutants. Ghrelin did not restore either GHRH binding or GH secretion in vitro. These studies show an unexpectedly broad role for leptin with respect to maintaining somatotroph functions, including the regulation of PRL and TSH in subsets of somatotrophs that may be progenitor cells.
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Affiliation(s)
- Melody L Allensworth-James
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Angela K Odle
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Juchan Lim
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Alex N LaGasse
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Tiffany K Miles
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Linda L Hardy
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Anessa C Haney
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Melanie C MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Angus M MacNicol
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Gwen V Childs
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Cheng Y, Chen T, Song J, Teng Z, Wang C, Wang S, Lu G, Feng T, Qi Q, Xi Q, Liu S, Hao L, Zhang Y. Pituitary miRNAs target GHRHR splice variants to regulate GH synthesis by mediating different intracellular signalling pathways. RNA Biol 2020; 17:1754-1766. [PMID: 32508238 DOI: 10.1080/15476286.2020.1778295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Growth hormone (GH), whose synthesis and release are mainly regulated by intracellular signals mediated by growth hormone-releasing hormone receptor (GHRHR), is one of the major pituitary hormones and critical regulators of organism growth, metabolism, and immunoregulation. Pig GHRHR splice variants (SVs) may activate different signalling pathways via the variable C-terminal by alternative splicing, and SVs have the potential to change microRNA (miRNA) binding sites. In this study, we first confirmed the existence of pig GHRHR SVs (i.e., GHRHR, GHRHR SV1 and SV2) and demonstrated the inhibitory effects of critical pituitary miRNAs (i.e., let-7e and miR-328-5p) on GH synthesis and cell proliferation of primary pituitary cells. The SVs of GHRHR targeted by let-7e and miR-328-5p were predicted via bioinformatics analysis and verified by performing dual-luciferase reporter assays and detecting the expression of target transcripts. The differential responses of let-7e, and miR-328-5p to GH-releasing hormone and the changes in signalling pathways mediated by GHRHR suggested that let-7e and miR-328-5p were involved in GH synthesis mediated by GHRHR SVs, indicating that the two miRNAs played different roles by different ways. Finally, results showed that the protein coded by the GHRHR transcript regulated GH through the NO/NOS signalling pathway, whereas that coded by SV1 and SV2 regulated GH through the PKA/CREB signalling pathway, which was confirmed by the changes in signalling pathways after transfecting the expression vectors of GHRHR SVs to GH3 cells. To the best of our knowledge, this paper is the first to report pituitary miRNAs regulate GH synthesis by targeting the different SVs of GHRHR.
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Affiliation(s)
- Yunyun Cheng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China.,Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Jie Song
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Zhaohui Teng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China.,Research and Development Centre, Dalian Mogue Biotech Co., Ltd , Dalian, China
| | - Chunli Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Siyao Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Guanhong Lu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Tianqi Feng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Qien Qi
- School of Life Science and Engineering, Foshan University , Foshan China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
| | - Songcai Liu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Linlin Hao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University , Changchun, China
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University , Guangzhou, China
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9
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Cheng Y, Chen T, Song J, Qi Q, Wang C, Xi Q, Liu S, Hao L, Zhang Y. miR-709 inhibits GHRP6 induced GH synthesis by targeting PRKCA in pituitary. Mol Cell Endocrinol 2020; 506:110763. [PMID: 32084499 DOI: 10.1016/j.mce.2020.110763] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/02/2020] [Accepted: 02/18/2020] [Indexed: 02/07/2023]
Abstract
Pituitary growth hormone (GH) plays an essential role in processes of organism growth and metabolism. MicroRNA (miRNA) could also participate in diverse biological processes. However, the role of miRNA in the regulation of pituitary GH during the growth process remains unclear. In this study, we firstly confirmed that the second highly expressed pituitary miRNA (miR-709) significantly inhibited the GH synthesis and suppressed the viability of GH3 cells. The bioinformatics analysis and dual luciferase report system were used to ascertain the PRKCA is the direct target gene of miR-709, which is the coding gene of PKCα. Then the transcription and translation levels of Prkca were obvious reduced by the over-expression of miR-709 in GH3 cells, followed by the inhibition of the transcription factor (CREB1) of Gh1 gene and the ERK1/2 signaling pathway or the possible cross-talk signaling pathway (cAMP/PKA signaling pathway) detected by western blot, suggesting that ERK1/2 maybe an important factor involved in the GH3 cell viability mediated by PKCα. At last, GHRP6 increased PKCα and GH expression but reduced miR-709 expression in vitro and vivo assays, and this conclusion was further confirmed by the result of GHRP6 attenuated the inhibition of miR-709 on GH expression. These findings will provide new molecular mechanism on the regulation of pituitary GH.
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Affiliation(s)
- Yunyun Cheng
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Ting Chen
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Jie Song
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Qien Qi
- School of Life Science and Engineering, Foshan University, Foshan, 528231, China
| | - Chunli Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Qianyun Xi
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China
| | - Songcai Liu
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China
| | - Linlin Hao
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, 5333 Xian Road, Changchun, 130062, China.
| | - Yongliang Zhang
- Guangdong Provincial Key Laboratory of Animal Nutritional Regulation, National Engineering Research Center for Breeding Swine Industry, Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, 483 Wushan Road, Guangzhou, 510642, China.
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Abstract
PURPOSE Pituitary tumor is the common primary brain tumor in humans. For further studying the pathogenesis and new therapeutic targets of pituitary adenoma, cell lines and primary cells are necessary tools. Different from primary cells that have short survival time and hormone secretion maintenance time, cell lines would be endowed with immortal characteristics under the help of gene modification. This review is to explore whether these cell lines still have similar pathophysiological changes in pituitary adenoma cells and methods to prolong the lifespan of pituitary adenoma primary cells. RESULTS In the cell lines summarized in the review, HP75, PDFS, HPA and GX were derived from human pituitary adenomas. It was found that the cell lines commonly used in articles published between January 2014 and July 2019 were GH3, AtT20, MMQ, GH4C1, HP75 and TtT/GF. Besides, it was glad that many methods had been used to prolong the lifespan and maintain characteristics of pituitary adenoma primary cells. CONCLUSION The paper reviews most of pituitary adenoma cell lines that have been successfully established since 1968 and the relevant situation of primary culture of pituitary adenoma cells. Obviously, it requires us to make more efforts to obtain human pituitary adenoma cell lines and prolong the lifespan of pituitary adenoma primary cells with maintaining their morphology and ability to secret hormones.
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Affiliation(s)
- Ziyan Zhu
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Weiwei Cui
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Dimin Zhu
- Department of Neurosurgery and Pituitary Tumor Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Nailin Gao
- Department of Neurosurgery and Pituitary Tumor Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yonghong Zhu
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China.
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Vázquez-Borrego MC, Fuentes-Fayos AC, Herrera-Martínez AD, Venegas-Moreno E, L-López F, Fanciulli A, Moreno-Moreno P, Alhambra-Expósito MR, Barrera-Martín A, Dios E, Blanco-Acevedo C, Solivera J, Granata R, Kineman RD, Gahete MD, Soto-Moreno A, Gálvez-Moreno MA, Castaño JP, Luque RM. Statins Directly Regulate Pituitary Cell Function and Exert Antitumor Effects in Pituitary Tumors. Neuroendocrinology 2020; 110:1028-1041. [PMID: 31940630 DOI: 10.1159/000505923] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 01/11/2020] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Pituitary neuroendocrine tumors (PitNETs), the most abundant of all intracranial tumors, entail severe comorbidities. First-line therapy is transsphenoidal surgery, but subsequent pharmacological therapy is often required. Unfortunately, many patients are/become unresponsive to available drugs (somatostatin analogues [SSAs]/dopamine agonists), underscoring the need for new therapies. Statins are well-known drugs commonly prescribed to treat hyperlipidemia/cardiovascular diseases, but can convey additional beneficial effects, including antitumor actions. The direct effects of statins on normal human pituitary or PitNETs are poorly known. Thus, we aimed to explore the direct effects of statins, especially simvastatin, on key functional parameters in normal and tumoral pituitary cells, and to evaluate the combined effects of simvastatin with metformin (MF) or SSAs. METHODS Effects of statins in cell proliferation/viability, hormone secretion, and signaling pathways were evaluated in normal pituitary cells from a primate model (Papio anubis), tumor cells from corticotropinomas, somatotropinomas, nonfunctioning pituitary tumors, and PitNET cell-lines (AtT20/GH3-cells). RESULTS All statins decreased AtT20-cell proliferation, simvastatin showing stronger effects. Indeed, simvastatin reduced cell viability and/or hormone secretion in all PitNETs subtypes and cell-lines, and ACTH/GH/PRL/FSH/LH secretion (but not expression), in primate cell cultures, by modulating MAPK/PI3K/mTOR pathways and expression of key receptors (GH-releasing hormone-receptor/ghrelin-R/Kiss1-R) regulating pituitary function. Addition of MF or SSAs did not enhance simvastatin antitumor effects. CONCLUSION Our data reveal direct antitumor effects of simvastatin on PitNET-cells, paving the way to explore these compounds as a possible tool to treat PitNETs.
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Affiliation(s)
- Mari C Vázquez-Borrego
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Antonio C Fuentes-Fayos
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Aura D Herrera-Martínez
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Eva Venegas-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla, Sevilla, Spain
| | - Fernando L-López
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Alessandro Fanciulli
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Sciences, University of Turin and Città Della Salute e Della Scienza Hopital, Turin, Italy
| | - Paloma Moreno-Moreno
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - María R Alhambra-Expósito
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Ana Barrera-Martín
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Elena Dios
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla, Sevilla, Spain
| | - Cristóbal Blanco-Acevedo
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Neurosurgery, HURS, Cordoba, Spain
| | - Juan Solivera
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Neurosurgery, HURS, Cordoba, Spain
| | - Riccarda Granata
- Division of Endocrinology, Diabetes and Metabolism, Department of Medical Sciences, University of Turin and Città Della Salute e Della Scienza Hopital, Turin, Italy
| | - Rhonda D Kineman
- Division of Research and Developments, Department of Medicine, Jesse Brown Veterans Affairs Medical Center, Section of Endocrinology, Diabetes, and Metabolism, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Manuel D Gahete
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Alfonso Soto-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla, Sevilla, Spain
| | - María A Gálvez-Moreno
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- Service of Endocrinology and Nutrition, IMIBIC, HURS, Cordoba, Spain
| | - Justo P Castaño
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain
- Reina Sofia University Hospital (HURS), Cordoba, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain
| | - Raúl M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain,
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, Spain,
- Reina Sofia University Hospital (HURS), Cordoba, Spain,
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, Spain,
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12
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Luque RM, Kineman RD. Neuronostatin exerts actions on pituitary that are unique from its sibling peptide somatostatin. J Endocrinol 2018; 237:217-227. [PMID: 29615476 DOI: 10.1530/joe-18-0135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 04/03/2018] [Indexed: 12/12/2022]
Abstract
Neuronostatin, a somatostatin gene-encoded peptide, exerts important physiological and metabolic actions in diverse tissues. However, the direct biological effects of neuronostatin on pituitary function of humans and primates are still unknown. This study used baboon (Papio anubis) primary pituitary cell cultures, a species that closely models human physiology, to demonstrate that neuronostatin inhibits basal, but not ghrelin-/GnRH-stimulated, growth hormone (GH) and luteinizing hormone (LH) secretion in a dose- and time-dependent fashion, without affecting the secretion of other pituitary hormones (prolactin, ACTH, FSH, thyroid-stimulating hormone (TSH)) or changing mRNA levels. Actions of neuronostatin differs from somatostatin which in this study reduced GH/PRL/ACTH/LH/TSH secretion and GH/PRL/POMC/LH gene expression. Remarkably, we found that inhibitory actions of neuronostatin are likely mediated through: (1) the orphan receptor GPCR107 (found to be highly expressed in pituitary compared to somatostatin-receptors), (2) common (i.e. adenylyl cyclase/protein kinase A/MAPK/extra-/intracellular Ca2+ mobilization, but not phospholipase C/protein kinase C/mTOR) and distinct (i.e. PI3K) signaling pathways than somatostatin and; (3) dissimilar molecular mechanisms than somatostatin (i.e. upregulation of GPCR107 and downregulation of GHS-R/Kiss1-R expression by neuronostatin and, upregulation of sst1-5 expression by somatostatin). Altogether, the results of this study provide the first evidence that there is a functional neuronostatin signaling circuit, unique from somatostatin, which may work in concert with somatostatin to fine-tune hormone release from somatostropes and gonadotropes.
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Affiliation(s)
- Raúl M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Cordoba, Spain
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Cordoba, Spain
- Hospital Universitario Reina Sofia (HURS), Cordoba, Spain
- CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Madrid, Spain
| | - Rhonda D Kineman
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Illinois at Chicago and Research and Development Division, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois, USA
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13
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Hernández-Ramírez LC, Trivellin G, Stratakis CA. Cyclic 3',5'-adenosine monophosphate (cAMP) signaling in the anterior pituitary gland in health and disease. Mol Cell Endocrinol 2018; 463:72-86. [PMID: 28822849 DOI: 10.1016/j.mce.2017.08.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 11/28/2022]
Abstract
The cyclic 3',5'-adenosine monophosphate (cAMP) was the first among the so-called "second messengers" to be described. It is conserved in most organisms and functions as a signal transducer by mediating the intracellular effects of multiple hormones and neurotransmitters. In this review, we first delineate how different members of the cAMP pathway ensure its correct compartmentalization and activity, mediate the terminal intracellular effects, and allow the crosstalk with other signaling pathways. We then focus on the pituitary gland, where cAMP exerts a crucial function by controlling the responsiveness of the cells to hypothalamic hormones, neurotransmitters and peripheral factors. We discuss the most relevant physiological functions mediated by cAMP in the different pituitary cell types, and summarize the defects affecting this pathway that have been reported in the literature. We finally discuss how a deregulated cAMP pathway is involved in the pathogenesis of pituitary disorders and how it affects the response to therapy.
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Affiliation(s)
- Laura C Hernández-Ramírez
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA
| | - Giampaolo Trivellin
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA
| | - Constantine A Stratakis
- Section on Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), 10 Center Drive, CRC, Room 1E-3216, Bethesda, MD 20892-1862, USA.
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14
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Vázquez-Borrego MC, Gahete MD, Martínez-Fuentes AJ, Fuentes-Fayos AC, Castaño JP, Kineman RD, Luque RM. Multiple signaling pathways convey central and peripheral signals to regulate pituitary function: Lessons from human and non-human primate models. Mol Cell Endocrinol 2018; 463:4-22. [PMID: 29253530 DOI: 10.1016/j.mce.2017.12.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 12/14/2017] [Accepted: 12/14/2017] [Indexed: 12/12/2022]
Abstract
The anterior pituitary gland is a key organ involved in the control of multiple physiological functions including growth, reproduction, metabolism and stress. These functions are controlled by five distinct hormone-producing pituitary cell types that produce growth hormone (somatotropes), prolactin (lactotropes), adrenocorticotropin (corticotropes), thyrotropin (thyrotropes) and follicle stimulating hormone/luteinizing hormone (gonadotropes). Classically, the synthesis and release of pituitary hormones was thought to be primarily regulated by central (neuroendocrine) signals. However, it is now becoming apparent that factors produced by pituitary hormone targets (endocrine and non-endocrine organs) can feedback directly to the pituitary to adjust pituitary hormone synthesis and release. Therefore, pituitary cells serve as sensors to integrate central and peripheral signals in order to fine-tune whole-body homeostasis, although it is clear that pituitary cell regulation is species-, age- and sex-dependent. The purpose of this review is to provide a comprehensive, general overview of our current knowledge of both central and peripheral regulators of pituitary cell function and associated intracellular mechanisms, focusing on human and non-human primates.
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Affiliation(s)
- M C Vázquez-Borrego
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain
| | - M D Gahete
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain
| | - A J Martínez-Fuentes
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain
| | - A C Fuentes-Fayos
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain
| | - J P Castaño
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain
| | - R D Kineman
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA; Jesse Brown Veterans Affairs Medical Center, Research and Development Division, Chicago, IL, USA
| | - R M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), 14004 Cordoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Cordoba, 14004 Cordoba, Spain; Reina Sofia University Hospital (HURS), 14004 Cordoba, Spain; CIBER Physiopathology of Obesity and Nutrition (CIBERobn), 14004 Cordoba, Spain; Agrifood Campus of International Excellence (ceiA3), 14004 Cordoba, Spain.
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15
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Sarmento-Cabral A, Peinado JR, Halliday LC, Malagon MM, Castaño JP, Kineman RD, Luque RM. Adipokines (Leptin, Adiponectin, Resistin) Differentially Regulate All Hormonal Cell Types in Primary Anterior Pituitary Cell Cultures from Two Primate Species. Sci Rep 2017; 7:43537. [PMID: 28349931 PMCID: PMC5640086 DOI: 10.1038/srep43537] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/25/2017] [Indexed: 12/27/2022] Open
Abstract
Adipose-tissue (AT) is an endocrine organ that dynamically secretes multiple hormones, the adipokines, which regulate key physiological processes. However, adipokines and their receptors are also expressed and regulated in other tissues, including the pituitary, suggesting that locally- and AT-produced adipokines might comprise a regulatory circuit that relevantly modulate pituitary cell-function. Here, we used primary pituitary cell-cultures from two normal nonhuman-primate species [Papio-anubis/Macaca-fascicularis] to determine the impact of different adipokines on the functioning of all anterior-pituitary cell-types. Leptin and resistin stimulated GH-release, a response that was blocked by somatostatin. Conversely, adiponectin decreased GH-release, and inhibited GHRH-, but not ghrelin-stimulated GH-secretion. Furthermore: 1) Leptin stimulated PRL/ACTH/FSH- but not LH/TSH-release; 2) adiponectin stimulated PRL-, inhibited ACTH- and did not alter LH/FSH/TSH-release; and 3) resistin increased ACTH-release and did not alter PRL/LH/FSH/TSH-secretion. These effects were mediated through the activation of common (AC/PKA) and distinct (PLC/PKC, intra-/extra-cellular calcium, PI3K/MAPK/mTOR) signaling-pathways, and by the gene-expression regulation of key receptors/transcriptional-factors involved in the functioning of these pituitary cell-types (e.g. GHRH/ghrelin/somatostatin/insulin/IGF-I-receptors/Pit-1). Finally, we found that primate pituitaries expressed leptin/adiponectin/resistin. Altogether, these and previous data suggest that local-production of adipokines/receptors, in conjunction with circulating adipokine-levels, might comprise a relevant regulatory circuit that contribute to the fine-regulation of pituitary functions.
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Affiliation(s)
- André Sarmento-Cabral
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
| | - Juan R Peinado
- Department of Medical Sciences, Faculty of Medicine of Ciudad Real, University of Castilla-La Mancha, Spain
| | - Lisa C Halliday
- Biologic Resources Laboratory, University of Illinois at Chicago, Chicago, Illinois, USA
| | - María M Malagon
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
| | - Justo P Castaño
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
| | - Rhonda D Kineman
- Research and Development Division, Jesse Brown Veterans Affairs Medical Center, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Medicine, Section of Endocrinology, Diabetes, and Metabolism, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Raúl M Luque
- Maimonides Institute of Biomedical Research of Cordoba (IMIBIC), Córdoba, Spain.,Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.,Hospital Universitario Reina Sofía (HURS), Córdoba, Spain.,CIBER de la Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain.,Campus de Excelencia Internacional Agroalimentario (ceiA3), Córdoba, Spain
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16
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Growth Hormone-Releasing Hormone and Its Analogues: Significance for MSCs-Mediated Angiogenesis. Stem Cells Int 2016; 2016:8737589. [PMID: 27774107 PMCID: PMC5059609 DOI: 10.1155/2016/8737589] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 06/19/2016] [Accepted: 07/03/2016] [Indexed: 02/08/2023] Open
Abstract
Mesenchymal stromal cells (MSCs) are promising candidates for regenerative medicine because of their multipotency, immune-privilege, and paracrine properties including the potential to promote angiogenesis. Accumulating evidence suggests that the inherent properties of cytoprotection and tissue repair by native MSCs can be enhanced by various preconditioning stimuli implemented prior to cell transplantation. Growth hormone-releasing hormone (GHRH), a stimulator in extrahypothalamus systems including tumors, has attracted great attentions in recent years because GHRH and its agonists could promote angiogenesis in various tissues. GHRH and its agonists are proangiogenic in responsive tissues including tumors, and GHRH antagonists have been tested as antitumor agents through their ability to suppress angiogenesis and cell growth. GHRH-R is expressed by MSCs and evolving work from our laboratory indicates that treatment of MSCs with GHRH agonists prior to cell transplantation markedly enhanced the angiogenic potential and tissue reparative properties of MSCs through a STAT3 signaling pathway. In this review we summarized the possible effects of GHRH analogues on cell growth and development, as well as on the proangiogenic properties of MSCs. We also discussed the relationship between GHRH analogues and MSC-mediated angiogenesis. The analyses provide new insights into molecular pathways of MSCs-based therapies and their augmentation by GHRH analogues.
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17
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López Soto EJ, Agosti F, Cabral A, Mustafa ER, Damonte VM, Gandini MA, Rodríguez S, Castrogiovanni D, Felix R, Perelló M, Raingo J. Constitutive and ghrelin-dependent GHSR1a activation impairs CaV2.1 and CaV2.2 currents in hypothalamic neurons. ACTA ACUST UNITED AC 2015; 146:205-19. [PMID: 26283199 PMCID: PMC4555474 DOI: 10.1085/jgp.201511383] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 07/13/2015] [Indexed: 12/22/2022]
Abstract
Constitutive and ligand-dependent GHSR1a activity attenuates CaV2 current and hypothalamic GABA release through distinct mechanisms and signaling pathways. The growth hormone secretagogue receptor type 1a (GHSR1a) has the highest known constitutive activity of any G protein–coupled receptor (GPCR). GHSR1a mediates the action of the hormone ghrelin, and its activation increases transcriptional and electrical activity in hypothalamic neurons. Although GHSR1a is present at GABAergic presynaptic terminals, its effect on neurotransmitter release remains unclear. The activities of the voltage-gated calcium channels, CaV2.1 and CaV2.2, which mediate neurotransmitter release at presynaptic terminals, are modulated by many GPCRs. Here, we show that both constitutive and agonist-dependent GHSR1a activity elicit a strong impairment of CaV2.1 and CaV2.2 currents in rat and mouse hypothalamic neurons and in a heterologous expression system. Constitutive GHSR1a activity reduces CaV2 currents by a Gi/o-dependent mechanism that involves persistent reduction in channel density at the plasma membrane, whereas ghrelin-dependent GHSR1a inhibition is reversible and involves altered CaV2 gating via a Gq-dependent pathway. Thus, GHSR1a differentially inhibits CaV2 channels by Gi/o or Gq protein pathways depending on its mode of activation. Moreover, we present evidence suggesting that GHSR1a-mediated inhibition of CaV2 attenuates GABA release in hypothalamic neurons, a mechanism that could contribute to neuronal activation through the disinhibition of postsynaptic neurons.
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Affiliation(s)
- Eduardo Javier López Soto
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Francina Agosti
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Agustina Cabral
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Emilio Roman Mustafa
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Valentina Martínez Damonte
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Maria Alejandra Gandini
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute, 07000 México D.F., México
| | - Silvia Rodríguez
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Daniel Castrogiovanni
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Ricardo Felix
- Department of Cell Biology, Center for Research and Advanced Studies of the National Polytechnic Institute, 07000 México D.F., México
| | - Mario Perelló
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
| | - Jesica Raingo
- Laboratory of Electrophysiology and Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology (IMBICE), B1904CMA La Plata, Buenos Aires, Argentina
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18
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Ibáñez-Costa A, Gahete MD, Rivero-Cortés E, Rincón-Fernández D, Nelson R, Beltrán M, de la Riva A, Japón MA, Venegas-Moreno E, Gálvez MÁ, García-Arnés JA, Soto-Moreno A, Morgan J, Tsomaia N, Culler MD, Dieguez C, Castaño JP, Luque RM. In1-ghrelin splicing variant is overexpressed in pituitary adenomas and increases their aggressive features. Sci Rep 2015; 5:8714. [PMID: 25737012 PMCID: PMC4649711 DOI: 10.1038/srep08714] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 02/02/2015] [Indexed: 01/26/2023] Open
Abstract
Pituitary adenomas comprise a heterogeneous subset of pathologies causing serious comorbidities, which would benefit from identification of novel, common molecular/cellular biomarkers and therapeutic targets. The ghrelin system has been linked to development of certain endocrine-related cancers. Systematic analysis of the presence and functional implications of some components of the ghrelin system, including native ghrelin, receptors and the recently discovered splicing variant In1-ghrelin, in human normal pituitaries (n = 11) and pituitary adenomas (n = 169) revealed that expression pattern of ghrelin system suffers a clear alteration in pituitary adenomasas comparedwith normal pituitary, where In1-ghrelin is markedly overexpressed. Interestingly, in cultured pituitary adenoma cells In1-ghrelin treatment (acylated peptides at 100 nM; 24–72 h) increased GH and ACTH secretion, Ca2+ and ERK1/2 signaling and cell viability, whereas In1-ghrelin silencing (using a specific siRNA; 100 nM) reduced cell viability. These results indicate that an alteration of the ghrelin system, specially its In1-ghrelin variant, could contribute to pathogenesis of different pituitary adenomas types, and suggest that this variant and its related ghrelin system could provide new tools to identify novel, more general diagnostic, prognostic and potential therapeutic targets in pituitary tumors.
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Affiliation(s)
- Alejandro Ibáñez-Costa
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
| | - Manuel D Gahete
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
| | - Esther Rivero-Cortés
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
| | - David Rincón-Fernández
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
| | | | - Manuel Beltrán
- Department of Pathology, Puerta del Mar University Hospital, Cádiz
| | - Andrés de la Riva
- Service of Neurosurgery, Hospital Universitario Reina Sofia, 14004 Córdoba, Spain
| | - Miguel A Japón
- Department of Pathology, Hospital Universitario Virgen del Rocío, 41013 Seville, Spain
| | - Eva Venegas-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS), 41013 Seville, Spain
| | - Ma Ángeles Gálvez
- Service of Endocrinology and Nutrition, Hospital Universitario Reina Sofia, and Instituto Maimónides de Investigación Biomédica de Córdoba, 14004 Córdoba, Spain
| | - Juan A García-Arnés
- Department of Endocrinology and Nutrition, Carlos Haya Hospital, 29010 Málaga, Spain
| | - Alfonso Soto-Moreno
- Metabolism and Nutrition Unit, Hospital Universitario Virgen del Rocío, Instituto de Biomedicina de Sevilla (IBIS), 41013 Seville, Spain
| | | | - Natia Tsomaia
- IPSEN Bioscience, Cambridge, 02142 Massachusetts, USA
| | | | - Carlos Dieguez
- Department of Physiology, University of Santiago de Compostela, and CIBER Fisiopatología de la Obesidad y Nutrición, 15782 Santiago de Compostela, Spain
| | - Justo P Castaño
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
| | - Raúl M Luque
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofia; CIBER Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), 14014 Córdoba, Spain
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19
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Ibáñez-Costa A, Córdoba-Chacón J, Gahete MD, Kineman RD, Castaño JP, Luque RM. Melatonin regulates somatotrope and lactotrope function through common and distinct signaling pathways in cultured primary pituitary cells from female primates. Endocrinology 2015; 156:1100-10. [PMID: 25545385 PMCID: PMC4330310 DOI: 10.1210/en.2014-1819] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Melatonin (MT) is secreted by the pineal gland and exhibits a striking circadian rhythm in its release. Depending on the species studied, some pituitary hormones also display marked circadian/seasonal patterns and rhythms of secretion. However, the precise relationship between MT and pituitary function remains controversial, and studies focusing on the direct role of MT in normal pituitary cells are limited to nonprimate species. Here, adult normal primate (baboons) primary pituitary cell cultures were used to determine the direct impact of MT on the functioning of all pituitary cell types from the pars distalis. MT increased GH and prolactin (PRL) expression/release in a dose- and time-dependent fashion, a response that was blocked by somatostatin. However, MT did not significantly affect ACTH, FSH, LH, or TSH expression/release. MT did not alter GHRH- or ghrelin-induced GH and/or PRL secretions, suggesting that MT may activate similar signaling pathways as ghrelin/GHRH. The effects of MT on GH/PRL release, which are likely mediated through MT1 receptor, involve both common (adenylyl cyclase/protein kinase A/extracellular calcium-channels) and distinct (phospholipase C/intracellular calcium-channels) signaling pathways. Actions of MT on pituitary cells also included regulation of the expression of other key components for the control of somatotrope/lactotrope function (GHRH, ghrelin, and somatostatin receptors). These results show, for the first time in a primate model, that MT directly regulates somatotrope/lactotrope function, thereby lending support to the notion that the actions of MT on these cells might substantially contribute to the define daily patterns of GH and PRL observed in primates and perhaps in humans.
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Affiliation(s)
- Alejandro Ibáñez-Costa
- Department of Cell Biology, Physiology, and Immunology (A.I.-C., J.C.-C., M.D.G., J.P.C., R.M.L.), University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofia; Centro de Investigación Biomédica en Red Fisiopatología de la Obesidad y Nutrición; and Campus de Excelencia Internacional Agroalimentario (ceiA3), E-14014 Córdoba, Spain; and Department of Medicine (J.C.-C., R.D.K.), Section of Endocrinology, Diabetes, and Metabolism, University of Illinois at Chicago and Research and Development Division, Jesse Brown Veterans Affairs Medical Center, Chicago, Illinois 60612
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20
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Luque RM, Córdoba-Chacón J, Ibáñez-Costa A, Gesmundo I, Grande C, Gracia-Navarro F, Tena-Sempere M, Ghigo E, Gahete MD, Granata R, Kineman RD, Castaño JP. Obestatin plays an opposite role in the regulation of pituitary somatotrope and corticotrope function in female primates and male/female mice. Endocrinology 2014; 155:1407-17. [PMID: 24484169 PMCID: PMC3959609 DOI: 10.1210/en.2013-1728] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Obestatin is a 23-amino-acid amidated peptide that is encoded by the ghrelin gene. Previous studies have shown obestatin can modulate the hypothalamic neuronal circuitry that regulates pituitary function, perhaps by modulating the actions of ghrelin. However, the direct actions of obestatin on pituitary function remain controversial. Here, primary pituitary cell cultures from a nonhuman primate (baboon) and mice were used to test the effects of obestatin on pituitary hormone expression and secretion. In pituitary cultures from both species, obestatin had no effect on prolactin, LH, FSH, or TSH expression/release. Conversely, obestatin stimulated proopiomelanocortin expression and ACTH release and inhibited GH expression/release in vitro, actions that were also observed in vivo in mice treated with obestatin. In vitro, obestatin inhibited the stimulatory actions of ghrelin on GH but not ACTH release. The inhibitory effect of obestatin on somatotrope function was associated with an overall reduction in pituitary transcription factor-1 and GHRH receptor mRNA levels in vitro and in vivo as well as a reduction in hypothalamic GHRH and ghrelin expression in vivo. The stimulatory effect of obestatin on ACTH was associated with an increase in pituitary CRF receptors. Obestatin also reduced the expression of pituitary somatostatin receptors (sst1/sst2), which could serve to modify its impact on hormone secretion. The in vitro actions of obestatin on both GH and ACTH release required the adenylyl cyclase and MAPK routes. Taken together, our results provide evidence that obestatin can act directly at the pituitary to control somatotrope and corticotrope function, and these effects are conserved across species.
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Affiliation(s)
- Raúl M Luque
- Department of Cell Biology, Physiology, and Immunology (R.M.L., J.C.-C., A.I.-C., F.G.-N., M.T.-S., M.D.G., J.P.C.), University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba, Hospital Universitario Reina Sofia, and Centros de Investigación Biomédica en Red (CIBER) Fisiopatología de la Obesidad y Nutrición, E-14014 Córdoba, Spain; Department of Medicine (J.C.-C., R.D.K.), University of Illinois at Chicago, and Jesse Brown Veterans Affairs Medical Center (J.C.-C., R.D.K.), Research and Development Division, Chicago, Illinois 60612; and Department of Medical Sciences (I.G., C.G., E.G., R.G.), University of Torino, 10126 Torino, Italy
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Gordon M, Thompson Jr. D, McKeever K. Effects of exogenous ghrelin infusion on feed intake and metabolic parameters of energy homeostasis in Standardbred mares. COMPARATIVE EXERCISE PHYSIOLOGY 2014. [DOI: 10.3920/cep144002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Six Standardbred mares (age 12±2 years, body weight 502±63 kg; mean ± standard deviation) were given 1.6 µg/kg acylated human ghrelin or vehicle treatment as an intravenous bolus in a randomised, cross-over design to test the hypothesis that exogenous ghrelin infusion would increase feed intake and alter metabolic parameters of energy homeostasis, leptin, glucose, insulin and cortisol. After the horses had initial access to hay cubes for 1.5 h, doses were given and hay cubes were available once again. Leftover feed was weighed 6 times over each of the 24 h testing periods. Blood samples for measurement of active ghrelin, growth hormone, leptin, glucose, insulin and cortisol were taken at time 0 (immediately before infusion) and 20, 40, 60, 80, 100, 120, 240, 480, and 720 min post-infusion. Every 10 min, the horses’ behaviour was recorded for eating, drinking, resting, and other behaviours. Ghrelin infusion did not increase (P≯0.05) feed intake in the mares as a group, but did increase feed intake (P<0.04) in horses that had the highest growth hormone response to ghrelin infusion. Plasma concentrations of active ghrelin growth hormone, glucose, insulin and cortisol were all increased (P<0.05) by ghrelin infusion. There was no significant change in plasma leptin concentration due to treatment. Ghrelin infusion did not cause a significant change in the number of eating episodes either 2 h post-treatment or for the 24 h testing period. Regression analysis suggests that the increase in feed intake in horses with the highest growth hormone response to ghrelin infusion may be due to their lower (P<0.05) body condition score and % body fat compared with horses that did not increase feed intake and had lower growth hormone response to ghrelin infusion.
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Affiliation(s)
- M.E. Gordon
- Department of Animal Sciences, Rutgers – The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901, USA
| | - D.L. Thompson Jr.
- Department of Animal Sciences, 105 J.B. Francioni Hall, Louisiana State University, Baton Rouge, LA 70803, USA
| | - K.H. McKeever
- Department of Animal Sciences, Rutgers – The State University of New Jersey, 84 Lipman Drive, New Brunswick, NJ 08901, USA
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Gahete MD, Rincón-Fernández D, Villa-Osaba A, Hormaechea-Agulla D, Ibáñez-Costa A, Martínez-Fuentes AJ, Gracia-Navarro F, Castaño JP, Luque RM. Ghrelin gene products, receptors, and GOAT enzyme: biological and pathophysiological insight. J Endocrinol 2014; 220:R1-24. [PMID: 24194510 DOI: 10.1530/joe-13-0391] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ghrelin is a 28-amino acid acylated hormone, highly expressed in the stomach, which binds to its cognate receptor (GHSR1a) to regulate a plethora of relevant biological processes, including food intake, energy balance, hormonal secretions, learning, inflammation, etc. However, ghrelin is, in fact, the most notorious component of a complex, intricate regulatory system comprised of a growing number of alternative peptides (e.g. obestatin, unacylated ghrelin, and In1-ghrelin, etc.), known (GHSRs) and, necessarily unknown receptors, as well as modifying enzymes (e.g. ghrelin-O-acyl-transferase), which interact among them as well as with other regulatory systems in order to tightly modulate key (patho)-physiological processes. This multiplicity of functions and versatility of the ghrelin system arise from a dual, genetic and functional, complexity. Importantly, a growing body of evidence suggests that dysregulation in some of the components of the ghrelin system can lead to or influence the development and/or progression of highly concerning pathologies such as endocrine-related tumors, inflammatory/cardiovascular diseases, and neurodegeneration, wherein these altered components could be used as diagnostic, prognostic, or therapeutic targets. In this context, the aim of this review is to integrate and comprehensively analyze the multiple components and functions of the ghrelin system described to date in order to define and understand its biological and (patho)-physiological significance.
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Affiliation(s)
- Manuel D Gahete
- Department of Cell Biology, Physiology and Immunology, Campus Universitario de Rabanales, Edificio Severo Ochoa (C6), Planta 3, University of Córdoba, 14014-Córdoba; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), University of Córdoba; Reina Sofia University Hospital, Córdoba; and CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Córdoba, Spain
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23
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Qian Y, Yan A, Lin H, Li W. Molecular characterization of the GHRH/GHRH-R and its effect on GH synthesis and release in orange-spotted grouper (Epinephelus coioides). Comp Biochem Physiol B Biochem Mol Biol 2012; 163:229-37. [PMID: 22750400 DOI: 10.1016/j.cbpb.2012.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/20/2012] [Accepted: 06/20/2012] [Indexed: 11/20/2022]
Abstract
Growth hormone-releasing hormone (GHRH) is a hypothalamic neuropeptide that stimulates growth hormone (GH) synthesis and secretion in the pituitary gland. In this paper, the full-length cDNAs of orange-spotted grouper GHRH and its receptor (GHRH-R) were cloned. The grouper GHRH cDNA is 713 bp in length and encodes a 141-aa precursor that includes an 18-aa signal peptide, a 27-aa mature GHRH mature peptide and a 47-aa carboxyl terminus. The grouper GHRH-R cDNA sequence is 1495 bp in length, encoding a 422-aa receptor with seven transmembrane domains. Tissue distribution analyses showed that both GHRH and GHRH-R mRNAs were predominantly expressed in the brain, while the GHRH-R mRNA was also abundantly detected in the pituitary gland. Both GHRH and GHRH-R mRNAs were expressed throughout embryonic development from the multi-cell stage to the newly hatched larvae stage, and the highest GHRH and GHRH-R expressions appeared at the brain vesicle stage and the heart stage, respectively. In vitro studies performed on the grouper pituitary primary cells showed that a synthetic grouper GHRH-NH(2) increased both GH mRNA expression and GH protein release in a dose-dependent manner. Together, these results suggest that the newly obtained grouper GHRH was able to stimulate GH synthesis and release, similar to its mammalian counterparts.
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Affiliation(s)
- Yuehua Qian
- State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PR China
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24
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Iranmanesh A, Lawson D, Veldhuis JD. Distinct metabolic surrogates predict basal and rebound GH secretion after glucose ingestion in men. J Clin Endocrinol Metab 2012; 97:2172-9. [PMID: 22472562 PMCID: PMC3387415 DOI: 10.1210/jc.2011-3317] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CONTEXT GH secretion declines rapidly after glucose ingestion and then recovers to higher-than-baseline levels (rebound GH release). HYPOTHESIS Selective metabolic markers predict the magnitude of glucose-suppressed GH release and postglucose rebound-like GH secretion. DESIGN Prospectively randomized crossover study of GH secretion after glucose vs. water ingestion. SETTING The study was conducted at a clinical translational research center. PARTICIPANTS Sixty-nine healthy men aged 19-78 yr with a body mass index of 18-39 kg/m(2) participated in the study. OUTCOMES OUTCOMES included nadir vs. peak GH concentrations and basal vs. pulsatile GH secretion. RESULTS Mean nadir GH concentrations were determined positively by sex hormone binding globulin (SHBG) after glucose administration (R(2) = 0.088, P = 0.0077). Peak rebound GH concentrations were related positively to adiponectin and negatively to computed tomography-estimated abdominal visceral fat (AVF) (R(2) = 0.182, P = 0.00049) after glucose ingestion. Deconvolution analysis showed that SHBG specifically predicted basal (nonpulsatile) GH secretion after glucose exposure (R(2) = 0.153, P = 0.00052). In contrast, together exercise history and adiponectin (both positively) and AVF (negatively) predicted pulsatile GH escape after glucose suppression (R(2) = 0.206, P = 0.00043). Moreover, adiponectin uniquely determined the size (mass), and AVF the mode (duration), of GH secretory bursts after glucose exposure (both P < 0.006). CONCLUSION Glucose ingestion provides a clinical model for investigating complementary metabolic surrogates that determine suppression and recovery of basal and pulsatile GH secretion in healthy men.
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Affiliation(s)
- Ali Iranmanesh
- Endocrine Research Unit, Mayo School of Graduate Medical Education, Center for Translational Science Activities, Mayo Clinic, Rochester, Minnesota 55905, USA
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25
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Córdoba-Chacón J, Gahete MD, Culler MD, Castaño JP, Kineman RD, Luque RM. Somatostatin dramatically stimulates growth hormone release from primate somatotrophs acting at low doses via somatostatin receptor 5 and cyclic AMP. J Neuroendocrinol 2012; 24:453-63. [PMID: 22129035 DOI: 10.1111/j.1365-2826.2011.02261.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Somatostatin and cortistatin have been shown to act directly on pituitary somatotrophs to inhibit growth hormone (GH) release. However, previous results from nonprimate species indicate that these peptides can also directly stimulate GH secretion, at low concentrations. The relevance of this phenomenon in a nonhuman primate model was investigated in the present study by testing the impact of somatostatin/cortistatin on GH release in primary pituitary cell cultures from baboons. High doses (> 10(-10) m) of somatostatin/cortistatin did not alter basal GH secretion but blocked GH-releasing hormone (GHRH)- and ghrelin-induced GH release. However, at low concentrations (10(-17)-10(-13) m), somatostatin/cortistatin dramatically stimulated GH release to levels comparable to those evoked by GHRH or ghrelin. Use of somatostatin receptor (sst) specific agonists/antagonists, and signal transduction blockers indicated that sst2 and sst1 activation via intact adenylate cylcase and mitogen-activated protein kinase systems mediated the inhibitory actions of high-concentration somatostatin. By contrast, the stimulatory actions of low-dose somatostatin on GH release were mediated by sst5 signalling through adenylate cylcase/cAMP/protein kinase A and intracellular Ca(2+) pathways, and were additive with ghrelin (not GHRH). Notably, low-concentrations of somatostatin, similar to sst5-agonists, inhibited prolactin release. These results clearly demonstrate that the ultimate impact of somatostatin/cortistatin on hormone release is dose-dependent, cell type-selective and receptor-specific, where the stimulatory effects of low-concentration somatostatin/cortistatin on GH release extend to primates, thereby supporting the notion that this action is relevant in regulating GH secretion in humans.
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Affiliation(s)
- J Córdoba-Chacón
- Department of Cell Biology, Physiology and Immunology, University of Cordoba and Reina Sofia University Hospital, Instituto Maimónides de Investigación Biomédica de Córdoba, and CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain
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26
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Anderson LL, Scanes CG. Nanobiology and physiology of growth hormone secretion. Exp Biol Med (Maywood) 2012; 237:126-42. [DOI: 10.1258/ebm.2011.011306] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Growth hormone (GH) secretion is controlled by hypothalamic releasing hormones from the median eminence together with hormones and neuropeptides produced by peripheral organs. Secretion of GH involves movement of secretory vesicles along microtubules, transient ‘docking’ with the porosome in the cell membrane and subsequent release of GH. Release of GH is stimulated by GH releasing hormone (GHRH) and inhibited by somatostatin (SRIF). Ghrelin may be functioning to stimulate GH release from somatotropes acting via the GH secretagogue (GHS) receptor (GHSR). However, recent physiological studies militate against this. In addition, ghrelin does influence GH release acting within the hypothalamus. Release of GH from the somatotropes involves the GH-containing secretory granules moving close to the cell surface followed by transitory fusion of the secretory granules with the porosomes located in multiple secretory pits in the cell membrane. Other peptides/proteins can influence GH secretion, particularly in species of non-mammalian vertebrates.
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Affiliation(s)
- Lloyd L Anderson
- Department of Animal Science
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011
| | - Colin G Scanes
- Department of Biological Sciences, University of Wisconsin, Milwaukee, WI 53211, USA
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27
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Stengel A, Taché Y. Activation of somatostatin 2 receptors in the brain and the periphery induces opposite changes in circulating ghrelin levels: functional implications. Front Endocrinol (Lausanne) 2012; 3:178. [PMID: 23335913 PMCID: PMC3542632 DOI: 10.3389/fendo.2012.00178] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 12/17/2012] [Indexed: 12/26/2022] Open
Abstract
Somatostatin is an important modulator of neurotransmission in the central nervous system and acts as a potent inhibitor of hormone and exocrine secretion and regulator of cell proliferation in the periphery. These pleiotropic actions occur through interaction with five G protein-coupled somatostatin receptor subtypes (sst(1) (-) (5)) that are widely expressed in the brain and peripheral organs. The characterization of somatostatin's effects can be investigated by pharmacological or genetic approaches using newly developed selective sst agonists and antagonists and mice lacking specific sst subtypes. Recent evidence points toward a divergent action of somatostatin in the brain and in the periphery to regulate circulating levels of ghrelin, an orexigenic hormone produced by the endocrine X/A-like cells in the rat gastric mucosa. Somatostatin interacts with the sst(2) in the brain to induce an increase in basal ghrelin plasma levels and counteracts the visceral stress-related decrease in circulating ghrelin. By contrast, stimulation of peripheral somatostatin-sst(2) signaling results in the inhibition of basal ghrelin release and mediates the postoperative decrease in circulating ghrelin. The peripheral sst(2)-mediated reduction of plasma ghrelin is likely to involve a paracrine action of D cell-derived somatostatin acting on sst(2) bearing X/A-like ghrelin cells in the gastric mucosa. The other member of the somatostatin family, named cortistatin, in addition to binding to sst(1) (-) (5) also directly interacts with the ghrelin receptor and therefore may simultaneously modulate ghrelin release and actions at target sites bearing ghrelin receptors representing a link between the ghrelin and somatostatin systems.
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Affiliation(s)
- Andreas Stengel
- Division Psychosomatic Medicine and Psychotherapy, Department of Medicine, Obesity Center Berlin, Charité, Universitätsmedizin BerlinBerlin, Germany
- *Correspondence: Andreas Stengel, Division Psychosomatic Medicine and Psychotherapy, Department of Medicine, Obesity Center Berlin, Charité, Universitätsmedizin Berlin, Luisenstr. 13a, 10117 Berlin, Germany. e-mail: ; Yvette Taché, Digestive Diseases Division, CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women’s Health, Department of Medicine, VA Greater Los Angeles Health Care System, University of California at Los Angeles, CURE Building 115, Room 117, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA. e-mail:
| | - Yvette Taché
- Digestive Diseases Division, CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women’s Health, Department of Medicine, VA Greater Los Angeles Health Care System, University of California at Los AngelesLos Angeles, CA, USA
- *Correspondence: Andreas Stengel, Division Psychosomatic Medicine and Psychotherapy, Department of Medicine, Obesity Center Berlin, Charité, Universitätsmedizin Berlin, Luisenstr. 13a, 10117 Berlin, Germany. e-mail: ; Yvette Taché, Digestive Diseases Division, CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women’s Health, Department of Medicine, VA Greater Los Angeles Health Care System, University of California at Los Angeles, CURE Building 115, Room 117, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA. e-mail:
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28
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Córdoba-Chacón J, Gahete MD, Castaño JP, Kineman RD, Luque RM. Homologous and heterologous in vitro regulation of pituitary receptors for somatostatin, growth hormone (GH)-releasing hormone, and ghrelin in a nonhuman primate (Papio anubis). Endocrinology 2012; 153:264-72. [PMID: 22109886 PMCID: PMC3249678 DOI: 10.1210/en.2011-1677] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Secretion of GH by pituitary somatotrophs is primarily stimulated by GHRH and ghrelin and inhibited by somatostatin through the activation of specific receptors [GHRH receptor (GHRH-R), GH secretagogue receptor (GHS-R) and somatostatin receptors (sst1-5), respectively]. However, we have shown that somatostatin, at low doses, can also stimulate GH release, directly and specifically, in primary pituitary cultures from a nonhuman primate (baboons, Papio anubis) and pigs. To determine whether somatostatin, GHRH, and ghrelin can also regulate the expression of their receptors in primates, pituitary cultures from baboons were treated for 4 h with GHRH or ghrelin (10(-8) m) or with high (10(-7) m) and low (10(-15) m) doses of somatostatin, and GH release and expression levels of all receptors were measured. GHRH/ghrelin decreased the expression of their respective receptors (GHRH-R and GHS-R). Both peptides increased sst1, only GHRH decreased sst5 expression, whereas sst2 expression remained unchanged. The effects of GHRH/ghrelin were completely mimicked by forskolin (adenylate cyclase activator) and phorbol 12-myristate 13-acetate (protein kinase C activator), respectively, indicating the regulation of receptor subtype levels by GHRH and ghrelin involved distinct signaling pathways. In contrast, high-dose somatostatin did not alter GH release but increased sst1, sst2, and sst5 expression, whereas GHRH-R and GHS-R expression were unaffected. Interestingly, low-dose somatostatin increased GH release and sst1 mRNA but decreased sst5 and GHRH-R expression, similar to that observed for GHRH. Altogether, our data show for the first time in a primate model that the primary regulators of somatotroph function (GHRH/ghrelin/somatostatin) exert both homologous and heterologous regulation of receptor synthesis which is dose and subtype dependent and involves distinct signaling pathways.
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MESH Headings
- Animals
- Cells, Cultured
- Colforsin/pharmacology
- Gene Expression/drug effects
- Ghrelin/administration & dosage
- Growth Hormone-Releasing Hormone/administration & dosage
- In Vitro Techniques
- Papio anubis/genetics
- Papio anubis/metabolism
- Pituitary Gland/drug effects
- Pituitary Gland/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Ghrelin/genetics
- Receptors, Ghrelin/metabolism
- Receptors, LHRH/genetics
- Receptors, LHRH/metabolism
- Receptors, Somatostatin/agonists
- Receptors, Somatostatin/genetics
- Receptors, Somatostatin/metabolism
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Somatostatin/administration & dosage
- Swine
- Tetradecanoylphorbol Acetate/pharmacology
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Affiliation(s)
- Jose Córdoba-Chacón
- Department of Cell Biology, Physiology, and Immunology, University of Córdoba, E-14014 Córdoba, Spain
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29
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Chang JP, Habibi HR, Yu Y, Moussavi M, Grey CL, Pemberton JG. Calcium and other signalling pathways in neuroendocrine regulation of somatotroph functions. Cell Calcium 2011; 51:240-52. [PMID: 22137240 DOI: 10.1016/j.ceca.2011.11.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/01/2011] [Accepted: 11/07/2011] [Indexed: 12/22/2022]
Abstract
Relative to mammals, the neuroendocrine control of pituitary growth hormone (GH) secretion and synthesis in teleost fish involves numerous stimulatory and inhibitory regulators, many of which are delivered to the somatotrophs via direct innervation. Among teleosts, how multifactorial regulation of somatotroph functions are mediated at the level of post-receptor signalling is best characterized in goldfish. Supplemented with recent findings, this review focuses on the known intracellular signal transduction mechanisms mediating the ligand- and function-specific actions in multifactorial control of GH release and synthesis, as well as basal GH secretion, in goldfish somatotrophs. These include membrane voltage-sensitive ion channels, Na(+)/H(+) antiport, Ca(2+) signalling, multiple pharmacologically distinct intracellular Ca(2+) stores, cAMP/PKA, PKC, nitric oxide, cGMP, MEK/ERK and PI3K. Signalling pathways mediating the major neuroendocrine regulators of mammalian somatotrophs, as well as those in other major teleost study model systems are also briefly highlighted. Interestingly, unlike mammals, spontaneous action potential firings are not observed in goldfish somatotrophs in culture. Furthermore, three goldfish brain somatostatin forms directly affect pituitary GH secretion via ligand-specific actions on membrane ion channels and intracellular Ca(2+) levels, as well as exert isoform-specific action on basal and stimulated GH mRNA expression, suggesting the importance of somatostatins other than somatostatin-14.
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Affiliation(s)
- John P Chang
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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30
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Grey CL, Chang JP. Differential involvement of protein kinase C and protein kinase A in ghrelin-induced growth hormone and gonadotrophin release from goldfish (Carassius auratus) pituitary cells. J Neuroendocrinol 2011; 23:1273-87. [PMID: 21919972 DOI: 10.1111/j.1365-2826.2011.02221.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Ghrelin (GRLN) and its receptor have been identified and characterised in goldfish brain and the pituitary, and recent evidence shows that goldfish (g)GRLN(19) induces both growth hormone (GH) and maturational gonadotrophin (LH) release through an extracellular Ca(2+) -dependent mechanism in goldfish. To further understand the role of GRLN in hormone release, the present study examined the involvement of protein kinase C (PKC) and protein kinase A (PKA) in gGRLN(19) -induced GH and LH release and corresponding Ca(2+) signals in primary cultures of goldfish pituitary cells. Treatments with PKC inhibitors, Bis-II and Gö 6976, significantly reduced gGRLN(19) -induced GH and LH release and their corresponding intracellular Ca(2+) signals in identified somatotrophs and gonadotrophs, respectively. gGRLN(19) was unable to further stimulate hormone release or Ca(2+) signals when cells were pretreated with the PKC agonist, DiC8. PKA inhibitors, H-89 and KT 5720, inhibited gGRLN(19) -induced LH release and Ca(2+) signals in gonadotrophs but not GH release or Ca(2+) signals in somatotrophs. Interestingly, pretreatment of pituitary cells with the adenylate cyclase activator forskolin potentiated gGRLN(19) -induced GH, but not LH, release, although it had no effect on intracellular Ca(2+) signals in either cell type. Taken together, the results suggest that PKC is an important intracellular component in gGRLN(19) -induced GH and LH release, whereas PKA is involved in gGRLN(19) -elicited LH release. Furthermore, the PKA pathway potentiates gGRLN(19) -induced GH release via a Ca(2+) -independent mechanism. Overall, the present study provides insight into the neuroendocrine regulation of GH and LH release by elucidating the mechanistic aspects of GRLN, a hormone involved in many critical physiological processes, including pituitary functions.
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Affiliation(s)
- C L Grey
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
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31
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Córdoba-Chacón J, Gahete MD, Pozo-Salas AI, Martínez-Fuentes AJ, de Lecea L, Gracia-Navarro F, Kineman RD, Castaño JP, Luque RM. Cortistatin is not a somatostatin analogue but stimulates prolactin release and inhibits GH and ACTH in a gender-dependent fashion: potential role of ghrelin. Endocrinology 2011; 152:4800-12. [PMID: 21971153 PMCID: PMC3230064 DOI: 10.1210/en.2011-1542] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cortistatin (CST) and somatostatin (SST) evolve from a common ancestral gene and share remarkable structural, pharmacological, and functional homologies. Although CST has been considered as a natural SST-analogue acting through their shared receptors (SST receptors 1-5), emerging evidence indicates that these peptides might in fact exert unique roles via selective receptors [e.g. CST, not SST, binds ghrelin receptor growth hormone secretagogue receptor type 1a (GHS-R1a)]. To determine whether the role of endogenous CST is different from SST, we characterized the endocrine-metabolic phenotype of male/female CST null mice (cort-/-) at hypothalamic-pituitary-systemic (pancreas-stomach-adrenal-liver) levels. Also, CST effects on hormone expression/secretion were evaluated in primary pituitary cell cultures from male/female mice and female primates (baboons). Specifically, CST exerted an unexpected stimulatory role on prolactin (PRL) secretion, because both male/female cort-/- mice had reduced PRL levels, and CST treatment (in vivo and in vitro) increased PRL secretion, which could be blocked by a GHS-R1a antagonist in vitro and likely relates to the decreased success of female cort-/- in first-litter pup care at weaning. In contrast, CST inhibited GH and adrenocorticotropin-hormone axes in a gender-dependent fashion. In addition, a rise in acylated ghrelin levels was observed in female cort-/- mice, which were associated with an increase in stomach ghrelin/ghrelin O-acyl transferase expression. Finally, CST deficit uncovered a gender-dependent role of this peptide in the regulation of glucose-insulin homeostasis, because male, but not female, cort-/- mice developed insulin resistance. The fact that these actions are not mimicked by SST and are strongly gender dependent offers new grounds to investigate the hitherto underestimated physiological relevance of CST in the regulation of physiological/metabolic processes.
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32
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Luque RM, Gahete MD, Cordoba-Chacon J, Childs GV, Kineman RD. Does the pituitary somatotrope play a primary role in regulating GH output in metabolic extremes? Ann N Y Acad Sci 2011; 1220:82-92. [PMID: 21388406 DOI: 10.1111/j.1749-6632.2010.05913.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Circulating growth hormone (GH) levels rise in response to nutrient deprivation and fall in states of nutrient excess. Because GH regulates carbohydrate, lipid, and protein metabolism, defining the mechanisms by which changes in metabolism alter GH secretion will aid in our understanding of the cause, progression, and treatment of metabolic diseases. This review will summarize what is currently known regarding the impact of systemic metabolic signals on GH-axis function. In addition, ongoing studies using the Cre/loxP system to generate mouse models with selective somatotrope resistance to metabolic signals will be discussed, where these models will serve to enhance our understanding of the specific role the somatotrope plays in sensing the metabolic environment and adjusting GH output in metabolic extremes.
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Affiliation(s)
- Raul M Luque
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba, CIBER Fisiopatología de la Obesidad y Nutrición, Córdoba, Spain
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33
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Luque RM, Córdoba-Chacón J, Gahete MD, Navarro VM, Tena-Sempere M, Kineman RD, Castaño JP. Kisspeptin regulates gonadotroph and somatotroph function in nonhuman primate pituitary via common and distinct signaling mechanisms. Endocrinology 2011; 152:957-66. [PMID: 21209013 PMCID: PMC3198963 DOI: 10.1210/en.2010-1142] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Kisspeptins (Kps) have emerged as key players in the control of reproductive-axis function, in which they operate as primary regulators of hypothalamic GnRH release. In addition, recent data indicate that Kps can also directly act on the pituitary to stimulate LH and GH release in primary pituitary cell culture prepared from rats, cows, and sheep. We present herein evidence that Kps (specifically Kp-10) can also stimulate LH and GH release in primary pituitary cell cultures prepared from female baboons (Papio anubis), a species that more closely models human physiology. The stimulatory effect of Kp-10 on LH and GH release was dose and time dependent and enhanced the hormonal responses to their major regulators (GnRH for LH; GHRH/ghrelin for GH) without affecting the release of other pituitary hormones (TSH, FSH, ACTH, prolactin). Use of pharmacological intracellular signaling blockers indicated Kp-10 signals through phospholipase C, protein kinase C, MAPK, and intracellular Ca(2+) mobilization, but not adenylyl cyclase, protein kinase A, extracellular Ca(2+) influx (through L-type channels), or nitric oxide synthase, to stimulate both LH and GH release. Interestingly, blockade of mammalian target of rapamycin or phosphoinositol 3-kinase activity fully abolished the stimulatory effect of Kp-10 on LH but not GH release. Of note, estradiol enhanced the relative LH response to Kp-10, alone or in combination with GnRH. In sum, our data are the first to provide evidence that, in a primate model, there is a functional Kp-signaling system within the pituitary, which is dynamically regulated and may contribute to the direct control of gonadotropic and somatotropic axes.
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Affiliation(s)
- Raúl M Luque
- Department of Cell Biology, Physiology, and Immunology, Campus Universitario de Rabanales, Edificio Severo Ochoa, Planta 3, University of Córdoba, E-14014 Córdoba, Spain
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Córdoba-Chacón J, Gahete MD, Castaño JP, Kineman RD, Luque RM. Somatostatin and its receptors contribute in a tissue-specific manner to the sex-dependent metabolic (fed/fasting) control of growth hormone axis in mice. Am J Physiol Endocrinol Metab 2011; 300:E46-54. [PMID: 20943754 PMCID: PMC3023207 DOI: 10.1152/ajpendo.00514.2010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Somatostatin (SST) inhibits growth hormone (GH) secretion and regulates multiple processes by signaling through its receptors sst1-5. Differential expression of SST/ssts may contribute to sex-specific GH pattern and fasting-induced GH rise. To further delineate the tissue-specific roles of SST and sst1-5 in these processes, their expression patterns were evaluated in hypothalamus, pituitary, and stomach of male and female mice under fed/fasted conditions in the presence (wild type) or absence (SST-knockout) of endogenous SST. Under fed conditions, hypothalamic/stomach SST/ssts expression did not differ between sexes, whereas male pituitary expressed more SST and sst2A/2B/3/5A/5TMD2/5TMD1 and less sst1, and male pituitary cell cultures were more responsive to SST inhibitory actions on GH release compared with females. This suggests that local pituitary SST/ssts can contribute to the sexually dimorphic pattern of GH release. Fasting (48 h) reduced stomach sst2A/B and hypothalamic SST/sst2A expression in both sexes, whereas it caused a generalized downregulation of pituitary sst subtypes in male and of sst2A only in females. Thus, fasting can reduce SST sensitivity across tissues and SST input to the pituitary, thereby jointly contributing to enhance GH release. In SST-knockout mice, lack of SST differentially altered sst subtype expression levels in both sexes, supporting an important role for SST in sex-dependent control of GH axis. Evaluation of SST, IGF-I, and glucocorticoid effects on hypothalamic and pituitary cell cultures revealed that these hormones could directly account for alterations in sst2/5 expression in the physiological states examined. Taken together, these results indicate that changes in SST output and sensitivity can contribute critically to precisely define, in a tissue-dependent manner, the sex-specific metabolic regulation of the GH axis.
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Affiliation(s)
- José Córdoba-Chacón
- Department of Cell Biology, Physiology, and Immunology, University of Cordoba, Instituto Maimónides de Investigación Biomédica de Córdoba, and Centro de Investigacion Biomedica en Red Fisiopatología de la Obesidad y Nutrición, Cordoba, Spain
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35
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Taboada GF, Neto LV, Luque RM, Córdoba-Chacón J, de Oliveira Machado E, de Carvalho DP, Kineman RD, Gadelha MR. Impact of gsp oncogene on the mRNA content for somatostatin and dopamine receptors in human somatotropinomas. Neuroendocrinology 2011; 93:40-7. [PMID: 21079388 DOI: 10.1159/000322040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 10/13/2010] [Indexed: 12/27/2022]
Abstract
INTRODUCTION It has been reported in some series that gsp+ somatotropinomas are more sensitive to somatostatin analogues (SA) and dopamine's actions which may be related to their somatostatin receptor (SSTR) and dopamine receptor (DR) profile. No previous studies have been undertaken to evaluate the SSTR and DR profile related with the gsp status in somatotropinomas. OBJECTIVES To determine if (1) gsp status is correlated with response to octreotide LAR (LAR) and tumor expression patterns of SSTR1-5 and DR1-5 and (2) cAMP level can directly modulate SSTR and DR mRNA levels. METHODS Response to SA was evaluated by GH and IGF-I percent reduction after 3 and 6 months of treatment with LAR. Conventional PCR and sequencing were used to identify gsp+ tumors. Quantitative real-time PCR was used to determine SSTR and DR tumor expression. Primary pituitary cell cultures of primates were used to study whether SSTR and DR expression is regulated by forskolin. RESULTS The response to LAR did not significantly differ between patients with gsp+ and gsp- tumors; however, gsp+ tumors expressed higher levels of SSTR1, SSTR2, DR2 and a lower level of SSTR3. Forskolin increased SSTR1, SSTR2, DR1 and DR2 expression in cell cultures. CONCLUSION Elevated SSTR1, SSTR2, and DR2 tumor expression may help improve responsiveness to SA and DA therapy; however, this study may not have been appropriately powered to observe significant effects in the clinical response. Elevated cAMP levels could be directly responsible for the upregulation in SSTR1, SSTR2 and DR2 mRNA levels observed in gsp+ patients.
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de Sá LBPC, Nascif SO, Correa-Silva SR, Molica P, Vieira JGH, Dib SA, Lengyel AMJ. Effects of ghrelin, growth hormone-releasing peptide-6, and growth hormone-releasing hormone on growth hormone, adrenocorticotropic hormone, and cortisol release in type 1 diabetes mellitus. Metabolism 2010; 59:1536-42. [PMID: 20189610 DOI: 10.1016/j.metabol.2010.01.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Revised: 01/20/2010] [Accepted: 01/22/2010] [Indexed: 11/25/2022]
Abstract
In type 1 diabetes mellitus (T1DM), growth hormone (GH) responses to provocative stimuli are normal or exaggerated, whereas the hypothalamic-pituitary-adrenal axis has been less studied. Ghrelin is a GH secretagogue that also increases adrenocorticotropic hormone (ACTH) and cortisol levels, similarly to GH-releasing peptide-6 (GHRP-6). Ghrelin's effects in patients with T1DM have not been evaluated. We therefore studied GH, ACTH, and cortisol responses to ghrelin and GHRP-6 in 9 patients with T1DM and 9 control subjects. The GH-releasing hormone (GHRH)-induced GH release was also evaluated. Mean fasting GH levels (micrograms per liter) were higher in T1DM (3.5 ± 1.2) than in controls (0.6 ± 0.3). In both groups, ghrelin-induced GH release was higher than that after GHRP-6 and GHRH. When analyzing Δ area under the curve (ΔAUC) GH values after ghrelin, GHRP-6, and GHRH, no significant differences were observed in T1DM compared with controls. There was a trend (P = .055) to higher mean basal cortisol values (micrograms per deciliter) in T1DM (11.7 ± 1.5) compared with controls (8.2 ± 0.8). No significant differences were seen in ΔAUC cortisol values in both groups after ghrelin and GHRP-6. Mean fasting ACTH values were similar in T1DM and controls. No differences were seen in ΔAUC ACTH levels in both groups after ghrelin and GHRP-6. In summary, patients with T1DM have normal GH responsiveness to ghrelin, GHRP-6, and GHRH. The ACTH and cortisol release after ghrelin and GHRP-6 is also similar to controls. Our results suggest that chronic hyperglycemia of T1DM does not interfere with GH-, ACTH-, and cortisol-releasing mechanisms stimulated by these peptides.
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Affiliation(s)
- Larissa Bianca Paiva Cunha de Sá
- Division of Endocrinology, Universidade Federal de São Paulo, UNIFESP-EPM, Rua Pedro de Toledo 910, 04039-002-São Paulo, Brazil.
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Assessment of ghrelin, GHS-R, GH, and neurohormones in human fetal pituitary glands and central nervous system: an immunohistochemical study. Folia Histochem Cytobiol 2010; 47:505-10. [PMID: 20164039 DOI: 10.2478/v10042-009-0106-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this work was evaluation of expression of ghrelin and GHS-R1a receptor in somatotrops and in neuronal cells of brain tissue in the process of human fetal ontogenesis. Relations were also looked for between GHRH and SS in the pituitary and in the CNS neurones of the studied fetuses. The study was based on 8 pituitaries and 8 brains from fetuses in different periods of intrauterine life. The immunocytochemical technique was used. The presence of ghrelin, GHS-R was shown in the glandular part of the pituitary and CNS during the whole period of intrauterine life. Neurohormones in the stalk of the pituitary were found in fetuses from the 32nd week of pregnancy whereas in the CNS neurones these hormones could be detected throughout the whole period of intrauterine life. The results obtained suggest that stimulation of GH secretion by ghrelin is independent of the feedback concentration and these two hormones act like signals of metabolic balance. GH release by ghrelin in fetal life is independent of somatostatin. The hypothalamic-pituitary axis which regulates pulsatile GH release from the pituitary matures functionally in the third trimester of pregnancy independent of the previous anatomical differentiation.
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GHRP-6 induces CREB phosphorylation and growth hormone secretion via a protein kinase Csigma-dependent pathway in GH3 cells. ACTA ACUST UNITED AC 2010; 30:183-7. [PMID: 20407870 DOI: 10.1007/s11596-010-0210-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Indexed: 01/03/2023]
Abstract
This study examined the effect of GHRP-6, a known GHSs receptor agonist, on the phosphorylation of cAMP-responsive element-binding protein (CREB) and the underly mechanism. GH3 cells were cultured and subjected to different treatments as follows: GHRP-6, GHRP-6 plus GHRH, phorbol ester (PMA), an activator of PKC, alone or in combination with GHRP-6, Gö6983, a general inhibitor of PKCs, in the presence or absence of GHRP-6, rottlerin, an inhibitor of PKCs, alone or plus GHRP-6. The cells were transiently transfected with PKCsigma-specific siRNA and then treated with GHRP-6. GH level was measured by enzyme-linked immunosorbent assay (ELISA). The expression of phosphor-CREB, PKCsigma, PKCtheta and phosphor-PKCsigma was determined by Western blotting. The results showed that GHRP-6 stimulated GH secretion in both time- and dose-dependent manners and enhanced the effect of GHRH on GH secretion. GHRP-6 was also found to induce CREB phosphorylation. Moreover, GH secretion was enhanced by the PKC activator PMA and reduced by the PKC inhibitors (Gö6983, rottlerin) and knockdown of PKCsigma. PKCsigma could be activated by GHRP-6. It is concluded that PKC, especially PKCsigma, mediates CREB phosphorylation and GHRP-6-induced GH secretion.
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Ardiyanti A, Abe F, Kobashikawa H, Hirayama T, Sugino T, Suzuki K, Katoh K. Plasma hormone and metabolite concentrations involved in the somatotropic axis of Japanese Black heifers in association with growth hormone gene polymorphism. Domest Anim Endocrinol 2009; 37:243-9. [PMID: 19747793 DOI: 10.1016/j.domaniend.2009.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 07/14/2009] [Accepted: 07/15/2009] [Indexed: 10/20/2022]
Abstract
Bovine growth hormone (bGH) gene polymorphism of leucine (Leu)-threonine (Thr) (allele A), valine (Val)-Thr (allele B), and Val-methionine (Met) (allele C) at codons 127 and 172 was shown to relate with carcass trait variations in Japanese Black cattle. In this study, 10-mo-old Japanese Black heifers with growth hormone (GH) genotypes AA, AB, BB, AC, BC, and CC (N=141) were compared for basal GH, insulin-like growth factor-1 (IGF-1), insulin, ghrelin, glucose, and nonesterified fatty acid (NEFA) concentrations. Growth hormone release was also measured as response to growth hormone-releasing hormone (GHRH) (0.4 microg/kg body weight [BW]) using 18 heifers with GH genotypes AA, BB, and CC (n=6 for each group). The genotype AA heifers showed the greatest BW among genotypes (P<0.05). Genotype AC, BC, and CC heifers showed greater GH concentrations than genotype AA, AB, or BB heifers, in which genotype CC heifers had the highest concentrations (P<0.05). However, IGF-1 concentrations did not significantly differ. The genotype AA and BB heifers had a greater GH release at 60 min following GHRH injection than did the genotype CC heifers. The area under the curve (AUC; P<0.07) and incremental area (IA; P<0.08) of GH responses to the GHRH challenge tended to be the highest in the genotype AA heifers and the lowest in the genotype CC heifers. In conclusion, GH gene polymorphism altered GH, which may have contributed to differences in BW and carcass traits among genotypes.
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Affiliation(s)
- A Ardiyanti
- Department of Animal Physiology, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori, Aoba, Sendai, Japan.
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Correa-Silva SR, Sá LBPCD, Lengyel AMJ. [Ghrelin and growth hormone secretagogues (GHS): modulation of growth hormone secretion and therapeutic applications]. ACTA ACUST UNITED AC 2009; 52:726-33. [PMID: 18797578 DOI: 10.1590/s0004-27302008000500003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Accepted: 05/30/2008] [Indexed: 11/22/2022]
Abstract
Growth hormone-releasing hormone (GHRH) and somatostatin modulate growth hormone (GH) secretion. A third mechanism was discovered in the last decade, involving the action of growth hormone secretagogues (GHS). Ghrelin, the endogenous ligand of the GHS-receptor, is an acylated peptide mainly produced by the stomach, but also synthesized in the hypothalamus. This compound increases both GH release and food intake. Endogenous ghrelin might amplify the basic pattern of GH secretion, optimizing somatotroph responsiveness to GHRH, activating multiple interdependent intracellular pathways. However, its main site of action is the hypothalamus. In the current paper it is reviewed the available data on the discovery of this peptide, the mechanisms of action and possible physiological roles of the GHS and ghrelin on GH secretion, and finally, the possible therapeutic applications of these compounds.
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Affiliation(s)
- Silvia R Correa-Silva
- Disciplina de Endocrinologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP, Brazil.
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Gahete MD, Durán-Prado M, Luque RM, Martínez-Fuentes AJ, Quintero A, Gutiérrez-Pascual E, Córdoba-Chacón J, Malagón MM, Gracia-Navarro F, Castaño JP. Understanding the multifactorial control of growth hormone release by somatotropes: lessons from comparative endocrinology. Ann N Y Acad Sci 2009; 1163:137-53. [PMID: 19456335 DOI: 10.1111/j.1749-6632.2008.03660.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Control of postnatal growth is the main, but not the only, role for growth hormone (GH) as this hormone also contributes to regulating metabolism, reproduction, immunity, development, and osmoregulation in different species. Likely owing to this variety of group-specific functions, GH production is differentially regulated across vertebrates, with an apparent evolutionary trend to simplification, especially in the number of stimulatory factors governing substantially GH release. Thus, teleosts exhibit a multifactorial regulation of GH secretion, with a number of factors, from the newly discovered fish GH-releasing hormone (GHRH) to pituitary adenylate cyclase-activating peptide (PACAP) but also gonadotropin-releasing hormone, dopamine, corticotropin-releasing hormone, and somatostatin(s) directly controlling somatotropes. In amphibians and reptiles, GH secretion is primarily stimulated by the major hypothalamic peptides GHRH and PACAP and inhibited by somatostatin(s), while other factors (ghrelin, thyrotropin-releasing hormone) also influence GH release. Finally, in birds and mammals, primary control of GH secretion is exerted by a dual interplay between GHRH and somatostatin. In addition, somatotrope function is modulated by additional hypothalamic and peripheral factors (e.g., ghrelin, leptin, insulin-like growth factor-I), which together enable a balanced integration of feedback signals related to processes in which GH plays a relevant regulatory role, such as metabolic and energy status, reproductive, and immune function. Interestingly, in contrast to the high number of stimulatory factors impinging upon somatotropes, somatostatin(s) stand(s) as the main primary inhibitory regulator(s) for this cell type.
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Affiliation(s)
- Manuel D Gahete
- Department of Cell Biology, Physiology and Immunology, University of Córdoba, Cordoba, Spain
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Grey CL, Chang JP. Ghrelin-induced growth hormone release from goldfish pituitary cells involves voltage-sensitive calcium channels. Gen Comp Endocrinol 2009; 160:148-57. [PMID: 19038258 DOI: 10.1016/j.ygcen.2008.11.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 10/15/2008] [Accepted: 11/01/2008] [Indexed: 11/23/2022]
Abstract
Ghrelin (GRL) is a stimulator of growth hormone (GH) release in many organisms, including goldfish. As a first study to examine the signalling mechanisms mediating GRL action on GH release in goldfish, we tested the hypothesis that GLR induces GH release from goldfish pituitary cells by enhancing Ca(2+) entry through L-type voltage-sensitive Ca(2+) channels (LVSCCs) using perifusion GH release and fura-2/AM Ca(2+)-imaging experiments. Goldfish (g)GRL(19) at 1 nM elicited reversible and repeatable GH responses from dispersed goldfish mixed pituitary cultures. However, the lack of a dose-response relationship in sequential treatments with decreasing concentrations of gGRL(19) (ranging from 10 to 0.01 nM) implicated rapid desensitization of the GH response. Sequential applications of gGRL(19) (1 nM) and salmon GnRH (100 nM), a known Ca(2+)-dependent stimulator of GH release, increased intracellular free Ca(2+) levels ([Ca(2+)](i)) from the same identified somatotropes, suggesting co-expression of GRL and GnRH receptors on single cells. In contrast, 1 nM gGRL(19) failed to elicit GH release and elevation in [Ca(2+)](i) when the cells are incubated with nominally Ca(2+)-free media. When GH release and [Ca(2+)](i) increases were already stimulated by the LVSCC agonist Bay K8644 (10 microM), addition of 1 nM gGRL(19) did not further elevate these responses. Finally, the LVSCC inhibitors nifedipine (1 microM) and verapamil (1 microM) abolished 1nM gGRL(19)-induced GH release responses while nifedipine eliminated gGRL(19)-induced [Ca(2+)](i) increase. Taken together, the results of this study provide evidence that entry of extracellular Ca(2+) through LVSCCs is a key component of the GRL signalling pathway leading to GH release in the goldfish pituitary.
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Affiliation(s)
- Caleb L Grey
- Department of Biological Sciences, University of Alberta, Edmonton, Alta., Canada T6G 2E9
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Growth hormone-releasing hormone as an agonist of the ghrelin receptor GHS-R1a. Proc Natl Acad Sci U S A 2008; 105:20452-7. [PMID: 19088192 DOI: 10.1073/pnas.0811680106] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ghrelin synergizes with growth hormone-releasing hormone (GHRH) to potentiate growth hormone (GH) response through a mechanism not yet fully characterized. This study was conducted to analyze the role of GHRH as a potential ligand of the ghrelin receptor, GHS-R1a. The results show that hGHRH(1-29)NH(2) (GHRH) induces a dose-dependent calcium mobilization in HEK 293 cells stably transfected with GHS-R1a an effect not observed in wild-type HEK 293 cells. This calcium rise is also observed using the GHRH receptor agonists JI-34 and JI-36. Radioligand binding and cross-linking studies revealed that calcium response to GHRH is mediated by the ghrelin receptor GHS-R1a. GHRH activates the signaling route of inositol phosphate and potentiates the maximal response to ghrelin measured in inositol phosphate turnover. The presence of GHRH increases the binding capacity of (125)I-ghrelin in a dose dependent-fashion showing a positive binding cooperativity. In addition, confocal microscopy in CHO cells transfected with GHS-R1a tagged with enhanced green fluorescent protein shows that GHRH activates the GHS-R1a endocytosis. Furthermore, the selective GHRH-R antagonists, JV-1-42 and JMR-132, act also as antagonists of the ghrelin receptor GHS-R1a. Our findings suggest that GHRH interacts with ghrelin receptor GHS-R1a, and, in consequence, modifies the ghrelin-associated intracellular signaling pathway. This interaction may represent a form of regulation, which could play a putative role in the physiology of GH regulation and appetite control.
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45
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Luque RM, Park S, Kineman RD. Role of endogenous somatostatin in regulating GH output under basal conditions and in response to metabolic extremes. Mol Cell Endocrinol 2008; 286:155-68. [PMID: 18258353 DOI: 10.1016/j.mce.2007.12.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 11/28/2007] [Accepted: 12/05/2007] [Indexed: 01/26/2023]
Abstract
Somatostatin (SST) was first described over 30 years ago as a hypothalamic neuropeptide which inhibits GH release. Since that time a large body of literature has accumulated describing how endogenous SST mediates its effects on GH-axis function under normal conditions and in response to metabolic extremes. This review serves to summarize the key findings in this field with a focus on recent progress, much of which has been made possible by the availability of genetically engineered mouse models and SST receptor-specific agonists.
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Affiliation(s)
- Raul M Luque
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA
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46
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Luque RM, Kineman RD. Gender-dependent role of endogenous somatostatin in regulating growth hormone-axis function in mice. Endocrinology 2007; 148:5998-6006. [PMID: 17761762 DOI: 10.1210/en.2007-0946] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
It has been previously reported that male and female somatostatin (SST) knockout mice (Sst-/-) release more GH, compared with Sst+/+ mice, due to enhanced GH-secretory vesicle release. Endogenous SST may also regulate GH secretion by directly inhibiting GHRH-stimulated GH gene expression and/or by modulating hypothalamic GHRH input. To begin to explore these possibilities and to learn more about the gender-dependent role of SST in modulating GH-axis function, hypothalamic, pituitary, and liver components of the GH-axis were compared in male and female Sst+/+ and Sst-/- mice. Pituitary mRNA levels for GH and receptors for GHRH and ghrelin were increased in female Sst-/- mice, compared with Sst+/+ controls, and these changes were reflected by an increase in circulating GH and IGF-I. Elevated levels of IGF-I in female Sst-/- mice were associated with elevated hepatic mRNA levels for IGF-I, as well as for GH and prolactin receptors. Consistent with the role of GH/IGF-I in negative feedback regulation of hypothalamic function, GHRH mRNA levels were reduced in female Sst-/- mice, whereas cortistatin (CST) mRNA levels were unaltered. In contrast to the widespread impact of SST loss on GH-axis function in females, only circulating GH, hypothalamic CST, and hepatic prolactin receptor expression were up-regulated in Sst-/- male mice, compared with Sst+/+ controls. These results confirm and extend the sexually dimorphic role of SST on GH-axis regulation, and suggest that CST, a neuropeptide that acts through SST receptors to inhibit GH secretion, may serve a compensatory role in maintaining GH-axis function in Sst-/- male mice.
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MESH Headings
- Animals
- Blotting, Northern
- Cells, Cultured
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Deletion
- Growth Hormone/blood
- Growth Hormone/genetics
- Growth Hormone/metabolism
- Insulin-Like Growth Factor I/genetics
- Insulin-Like Growth Factor I/metabolism
- Liver/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Pituitary Gland/cytology
- Pituitary Gland/metabolism
- Radioimmunoassay
- Receptors, Ghrelin/blood
- Receptors, Ghrelin/genetics
- Receptors, Ghrelin/metabolism
- Receptors, Pituitary Hormone-Regulating Hormone/blood
- Receptors, Pituitary Hormone-Regulating Hormone/genetics
- Receptors, Pituitary Hormone-Regulating Hormone/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sex Factors
- Somatostatin/genetics
- Somatostatin/physiology
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Affiliation(s)
- Raul M Luque
- Jesse Brown Veterans Affairs Medical Center, Research and Development Division, M.P 151, West Side, 820 South Damen Avenue, Chicago, IL 60612, USA
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