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Das M, Gurusubramanian G, Roy VK. Immunolocalization of apelin receptor (APJ) in mouse seminiferous epithelium. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024; 341:450-457. [PMID: 38390701 DOI: 10.1002/jez.2801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 02/10/2024] [Accepted: 02/12/2024] [Indexed: 02/24/2024]
Abstract
The apelin receptor (APJ) belongs to the member of the G protein-coupled receptor family, and expression of APJ has been reported in the different cell types of testis. The seminiferous tubules in the testis can be identified as different stages (I-XII). It has been also suggested that different factors could be expressed in stage and cell-specific manner in the seminiferous tubules. Recently, we also shown that expression of APJ is developmentally regulated in the testis from PND1 to PND42. Therefore, we analyzed the expression of APJ in the testis of adult mice by immunohistochemistry. Immunohistochemistry showed that the APJ was highly specific for the round and elongated spermatids with stage-dependent changes. The seminiferous tubules at stages I-VII showed APJ immunostaining in the spermatid steps 1-8, not steps of 13-16. The seminiferous tubules at stages IX-XII showed APJ immunostaining in the spermatid steps 9-12. These results suggested the possible role of APJ in the spermiogenesis process. The intratesticular administration of APJ antagonist, ML221 showed a few round spermatids in the seminiferous tubules and some of the tubules with complete absence of round spermatid. Overall, we present evidence that APJ expression in spermatid is dependent on the stages of the seminiferous epithelium cycle and APJ could be involved in the differentiation of round spermatid to elongated spermatid.
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Affiliation(s)
- Milirani Das
- Department of Zoology, Mizoram University, Aizawl, Mizoram, India
| | | | - Vikas K Roy
- Department of Zoology, Mizoram University, Aizawl, Mizoram, India
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2
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Zhou XY, Ma JN, Shen YY, Xie XR, Ren W. Effects of Growth Hormone on Adult Human Gonads: Action on Reproduction and Sexual Function. Int J Endocrinol 2023; 2023:7492696. [PMID: 37064267 PMCID: PMC10104746 DOI: 10.1155/2023/7492696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 02/20/2023] [Accepted: 03/08/2023] [Indexed: 04/18/2023] Open
Abstract
Growth hormone (GH), which is commonly considered to be a promoter of growth and development, has direct and indirect effects on adult gonads that influence reproduction and sexual function of humans and nonhumans. GH receptors are expressed in adult gonads in some species including humans. For males, GH can improve the sensitivity of gonadotropins, contribute to testicular steroidogenesis, influence spermatogenesis possibly, and regulate erectile function. For females, GH can modulate ovarian steroidogenesis and ovarian angiogenesis, promote the development of ovarian cells, enhance the metabolism and proliferation of endometrial cells, and ameliorate female sexual function. Insulin-like growth factor-1 (IGF-1) is the main mediator of GH. In vivo, a number of the physiological effects of GH are mediated by GH-induced hepatic IGF-1 and local IGF-1. In this review, we highlight the roles of GH and IGF-1 in adult human gonads, clarify potential mechanisms, and explore the efficacy and the risk of GH supplementation in associated deficiency and assisted reproductive technologies. Besides, the effects of excess GH on adult human gonads are discussed as well.
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Affiliation(s)
- Xin-Yi Zhou
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Jia-Ni Ma
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Ya-Yin Shen
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Xue-Rui Xie
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
| | - Wei Ren
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
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3
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Mlyczyńska E, Kieżun M, Kurowska P, Dawid M, Pich K, Respekta N, Daudon M, Rytelewska E, Dobrzyń K, Kamińska B, Kamiński T, Smolińska N, Dupont J, Rak A. New Aspects of Corpus Luteum Regulation in Physiological and Pathological Conditions: Involvement of Adipokines and Neuropeptides. Cells 2022; 11:957. [PMID: 35326408 PMCID: PMC8946127 DOI: 10.3390/cells11060957] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 02/28/2022] [Accepted: 03/08/2022] [Indexed: 11/17/2022] Open
Abstract
The corpus luteum is a small gland of great importance because its proper functioning determines not only the appropriate course of the estrous/menstrual cycle and embryo implantation, but also the subsequent maintenance of pregnancy. Among the well-known regulators of luteal tissue functions, increasing attention is focused on the role of neuropeptides and adipose tissue hormones-adipokines. Growing evidence points to the expression of these factors in the corpus luteum of women and different animal species, and their involvement in corpus luteum formation, endocrine function, angiogenesis, cells proliferation, apoptosis, and finally, regression. In the present review, we summarize the current knowledge about the expression and role of adipokines, such as adiponectin, leptin, apelin, vaspin, visfatin, chemerin, and neuropeptides like ghrelin, orexins, kisspeptin, and phoenixin in the physiological regulation of the corpus luteum function, as well as their potential involvement in pathologies affecting the luteal cells that disrupt the estrous cycle.
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Affiliation(s)
- Ewa Mlyczyńska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
| | - Marta Kieżun
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (M.K.); (E.R.); (B.K.); (T.K.); (N.S.)
| | - Patrycja Kurowska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
| | - Monika Dawid
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
| | - Karolina Pich
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
| | - Natalia Respekta
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
| | - Mathilde Daudon
- Unité Physiologie de la Reproduction et des Comportements, French National Institute for Agriculture, Food, and Environment, 37380 Nouzilly, France; (M.D.); (J.D.)
| | - Edyta Rytelewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (M.K.); (E.R.); (B.K.); (T.K.); (N.S.)
| | - Kamil Dobrzyń
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Barbara Kamińska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (M.K.); (E.R.); (B.K.); (T.K.); (N.S.)
| | - Tadeusz Kamiński
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (M.K.); (E.R.); (B.K.); (T.K.); (N.S.)
| | - Nina Smolińska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (M.K.); (E.R.); (B.K.); (T.K.); (N.S.)
| | - Joelle Dupont
- Unité Physiologie de la Reproduction et des Comportements, French National Institute for Agriculture, Food, and Environment, 37380 Nouzilly, France; (M.D.); (J.D.)
| | - Agnieszka Rak
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, 30-387 Krakow, Poland; (E.M.); (P.K.); (M.D.); (K.P.); (N.R.)
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Tenuta M, Carlomagno F, Cangiano B, Kanakis G, Pozza C, Sbardella E, Isidori AM, Krausz C, Gianfrilli D. Somatotropic-Testicular Axis: A crosstalk between GH/IGF-I and gonadal hormones during development, transition, and adult age. Andrology 2020; 9:168-184. [PMID: 33021069 DOI: 10.1111/andr.12918] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/31/2020] [Accepted: 09/28/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND The hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-somatotropic (HPS) axes are strongly interconnected. Interactions between these axes are complex and poorly understood. These interactions are characterized by redundancies in reciprocal influences at each level of regulation and the combination of endocrine and paracrine effects that change during development. OBJECTIVES To comprehensively review the crosstalk between the HPG and HPS axes and related pathological and clinical aspects during various life stages of male subjects. MATERIALS AND METHODS A thorough search of publications available in PubMed was performed using proper keywords. RESULTS Molecular studies confirmed the expressions of growth hormone (GH) and insulin-like growth factor-I (IGF-I) receptors on the HPG axis and reproductive organs, indicating a possible interaction between HPS and HPG axes at various levels. Insulin growth factors participate in sexual differentiation during fetal development, indicating that normal HPS axis activity is required for proper testicular development. IGF-I contributes to correct testicular position during minipuberty, determines linear growth during childhood, and promotes puberty onset and pace through gonadotropin-releasing hormone activation. IGF-I levels are high during transition age, even when linear growth is almost complete, suggesting its role in reproductive tract maturation. Patients with GH deficiency (GHD) and insensitivity (GHI) exhibit delayed puberty and impaired genital development; replacement therapy in such patients induces proper pubertal development. In adults, few studies have suggested that lower IGF-I levels are associated with impaired sperm parameters. DISCUSSION AND CONCLUSION The role of GH-IGF-I in testicular development remains largely unexplored. However, it is important to evaluate gonadic development in children with GHD. Additionally, HPS axis function should be evaluated in children with urogenital malformation or gonadal development alterations. Correct diagnosis and prompt therapeutic intervention are needed for healthy puberty, attainment of complete gonadal development during transition age, and fertility potential in adulthood.
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Affiliation(s)
- Marta Tenuta
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | | | - Biagio Cangiano
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - George Kanakis
- Athens Naval and Veterans Affairs Hospital, Athens, Greece
| | - Carlotta Pozza
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Emilia Sbardella
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Andrea M Isidori
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Csilla Krausz
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
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Ozkanli S, Basar MM, Selimoglu S, Erol B, Ozkanli O, Nurili F, Kahraman S. The ghrelin and orexin activity in testicular tissues of patients with idiopathic non-obstructive azoospermia. Kaohsiung J Med Sci 2018; 34:564-568. [PMID: 30309484 DOI: 10.1016/j.kjms.2018.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 03/25/2018] [Accepted: 04/10/2018] [Indexed: 10/28/2022] Open
Abstract
The aim of the present study is to evaluate the presence of ghrelin and orexin in the testicular tissue of patients who have undergone microscopic testicular sperm extraction (micro-TESE) due to idiopathic non-obstructive azoospermia. Seventy azoospermic cases were included in this study; serum hormone levels were measured and genetic investigations were performed. The patients were divided into two groups: micro-TESE (+) and micro-TESE (-). The number of Leydig cells and stained cells in the seminiferous tubules were counted under a light microscope, and we analyzed ghrelin and orexin activity. The relationship between serum hormone levels and ghrelin and orexin distributions in testicular tissue was evaluated according to micro-TESE results. While sperm was found in 33 cases (47.1%), micro-TESE was negative in 37 cases (52.9%). Peptide hormone activity in testicular tissue was higher in micro-TESE (+) cases. However, interstitial orexin (p = 0.038) and ghrelin (p = 0.002) activity showed statistically meaningful differences. Many different peptides, genes, and other unknown mechanisms play important roles in testicular function. In particular, the peptides orexin and ghrelin may play regulatory roles in testicular function in humans.
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Affiliation(s)
- Seyma Ozkanli
- Department of Pathology, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey.
| | | | | | - Bulent Erol
- Department of Urology, Faculty of Medicine, Istanbul Medeniyet University, Istanbul, Turkey
| | - Oguz Ozkanli
- Department of Anesthesiology, Memorial Sisli Hospital, Istanbul, Turkey
| | - Fuad Nurili
- Department of Radiology, Memorial Sloan Kettering Cancer Center, USA
| | - Semra Kahraman
- Department of IVF, Memorial Sisli Hospital, Istanbul, Turkey
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6
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Poretti MB, Frautschi C, Luque E, Bianconi S, Martini AC, Stutz G, Vincenti L, Santillán ME, Ponzio M, Schiöth HB, Fiol de Cuneo M, Carlini VP. Reproductive performance of male mice after hypothalamic ghrelin administration. Reproduction 2018; 156:121-132. [PMID: 29794024 DOI: 10.1530/rep-17-0535] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 05/22/2018] [Indexed: 12/17/2022]
Abstract
It has been demonstrated that food intake and reproductive physiology are both simultaneously modulated to optimize reproductive success under fluctuating metabolic conditions. Ghrelin (GHRL) is an orexigenic peptide identified as the endogenous ligand of the growth hormone secretagogue receptor that is being investigated for its potential role on reproduction. Considering that data available so far are still limited and characterization of GHRL action mechanism on the reproductive system has not been fully elucidated, we studied the participation of hypothalamus in GHRL effects on sperm functional activity, plasma levels of gonadotropins and histological morphology in mice testes after hypothalamic infusion of 0.3 or 3.0 nmol/day GHRL or artificial cerebrospinal fluid (ACSF) at different treatment periods. We found that GHRL 3.0 nmol/day administration for 42 days significantly reduced sperm concentration (GHRL 3.0 nmol/day = 14.05 ± 2.44 × 106/mL vs ACSF = 20.33 ± 1.35 × 106/mL, P < 0.05) and motility (GHRL 3.0 nmol/day = 59.40 ± 4.20% vs ACSF = 75.80 ± 1.40%, P < 0.05). In addition, histological studies showed a significant decrease percentage of spermatogonia (GHRL 3.0 nmol/day = 6.76 ± 0.68% vs ACSF = 9.56 ± 0.41%, P < 0.05) and sperm (GHRL 3.0 nmol/day = 24.24 ± 1.92% vs ACSF = 31.20 ± 3.06%, P < 0.05). These results were associated with a significant reduction in luteinizing hormone and testosterone plasma levels (P < 0.05). As GHRL is an orexigenic peptide, body weight and food intake were measured. Results showed that GHRL increases both parameters; however, the effect did not last beyond the first week of treatment. Results presented in this work confirm that central GHRL administration impairs spermatogenesis and suggest that this effect is mediated by inhibition of hypothalamic-pituitary-gonadal axis.
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Affiliation(s)
- María Belén Poretti
- INICSAFacultad de Ciencias Médicas (CONICET-FCM), Instituto de Fisiología, Córdoba, Argentina .,Department of NeuroscienceFunctional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Camila Frautschi
- Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Eugenia Luque
- INICSAFacultad de Ciencias Médicas (CONICET-FCM), Instituto de Fisiología, Córdoba, Argentina
| | - Santiago Bianconi
- Department of NeuroscienceFunctional Pharmacology, Uppsala University, Uppsala, Sweden.,Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Ana Carolina Martini
- INICSAFacultad de Ciencias Médicas (CONICET-FCM), Instituto de Fisiología, Córdoba, Argentina
| | - Graciela Stutz
- Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Laura Vincenti
- Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Maria Emilia Santillán
- Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Marina Ponzio
- INICSAFacultad de Ciencias Médicas (CONICET-FCM), Instituto de Fisiología, Córdoba, Argentina
| | - Helgi B Schiöth
- Department of NeuroscienceFunctional Pharmacology, Uppsala University, Uppsala, Sweden
| | - Marta Fiol de Cuneo
- Facultad de Ciencias MédicasUniversidad Nacional de Córdoba, Cátedra de Fisiología Humana, Córdoba, Argentina
| | - Valeria Paola Carlini
- INICSAFacultad de Ciencias Médicas (CONICET-FCM), Instituto de Fisiología, Córdoba, Argentina.,Department of NeuroscienceFunctional Pharmacology, Uppsala University, Uppsala, Sweden
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7
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Zhang W, Zhang Z, Chen J, Tong D. Ghrelin is expressed in the pregnant mammary glands of dairy goats and promotes the cell proliferation of mammary epithelial cells. Gen Comp Endocrinol 2018; 260:115-124. [PMID: 29366624 DOI: 10.1016/j.ygcen.2018.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/07/2017] [Accepted: 01/11/2018] [Indexed: 11/29/2022]
Abstract
Little is known about ghrelin's effects on cell proliferation in pregnant mammary epithelial cells (MECs) even though it is known to be a mitogen for a variety of other cell types. The objectives of this study were to evaluate the expression and localization of ghrelin and its functional receptor, GHSR-1a, in the mammary glands of dairy goats during pregnancy and to investigate the direct role of ghrelin in cell proliferation of primary cultured MECs. Compared to the early stage (days 30) of pregnancy, the abundance of transcripts and protein of ghrelin and GHSR-1a were significantly greater in mid- and late-phases (between days 90 and days 120) of pregnancy (p < .05). Immunohistochemistry analysis showed that ghrelin and GHSR-1a were predominantly localized in the alveolar and ductal mammary epithelial cells at various stages of pregnancy. In our in vitro experiments, ghrelin induced a dose- and time-dependent promotory effect on cell proliferation of MECs. At the dose of 103 pg/mL treatment 24 h, ghrelin augmented the expression of proliferation-related peptides (PCNA and cyclin B1). Furthermore, ghrelin promoted the expression of prolactin (PRL) and GHSR-1a in cultured MECs. Additionally, the stimulatory effects of ghrelin were blocked by d-Lys3-GHRP6, a selective antagonist of GHSR-1a. As the temporal changes in ghrelin and GHSR-1a expression in pregnant goat mammary glands coincided with the mammary growth and development during the pregnancy, activation of GHSR-1a signal transduction pathways by ghrelin may play a direct role in the regulation of mammary growth in dairy goats.
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Affiliation(s)
- Wenlong Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Zelin Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Jinxuan Chen
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China
| | - Dewen Tong
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
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8
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Sominsky L, Hodgson DM, McLaughlin EA, Smith R, Wall HM, Spencer SJ. Linking Stress and Infertility: A Novel Role for Ghrelin. Endocr Rev 2017; 38:432-467. [PMID: 28938425 DOI: 10.1210/er.2016-1133] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 07/24/2017] [Indexed: 12/23/2022]
Abstract
Infertility affects a remarkable one in four couples in developing countries. Psychological stress is a ubiquitous facet of life, and although stress affects us all at some point, prolonged or unmanageable stress may become harmful for some individuals, negatively impacting on their health, including fertility. For instance, women who struggle to conceive are twice as likely to suffer from emotional distress than fertile women. Assisted reproductive technology treatments place an additional physical, emotional, and financial burden of stress, particularly on women, who are often exposed to invasive techniques associated with treatment. Stress-reduction interventions can reduce negative affect and in some cases to improve in vitro fertilization outcomes. Although it has been well-established that stress negatively affects fertility in animal models, human research remains inconsistent due to individual differences and methodological flaws. Attempts to isolate single causal links between stress and infertility have not yet been successful due to their multifaceted etiologies. In this review, we will discuss the current literature in the field of stress-induced reproductive dysfunction based on animal and human models, and introduce a recently unexplored link between stress and infertility, the gut-derived hormone, ghrelin. We also present evidence from recent seminal studies demonstrating that ghrelin has a principal role in the stress response and reward processing, as well as in regulating reproductive function, and that these roles are tightly interlinked. Collectively, these data support the hypothesis that stress may negatively impact upon fertility at least in part by stimulating a dysregulation in ghrelin signaling.
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Affiliation(s)
- Luba Sominsky
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Deborah M Hodgson
- School of Psychology, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Eileen A McLaughlin
- School of Biological Sciences, Faculty of Science, The University of Auckland, Auckland 1010, New Zealand.,School of Environmental & Life Sciences, Faculty of Science and IT, The University of Newcastle, New South Wales 2308, Australia
| | - Roger Smith
- Mothers and Babies Research Centre, Hunter Medical Research Institute, Lookout Road, New Lambton Heights, New South Wales 2305, Australia.,Priority Research Centre in Reproductive Science, The University of Newcastle, New South Wales 2308, Australia
| | - Hannah M Wall
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
| | - Sarah J Spencer
- School of Health and Biomedical Sciences, RMIT University, Melbourne, Victoria 3083, Australia
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9
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Bianchi E, Boekelheide K, Sigman M, Hall SJ, Hwang K. Ghrelin modulates testicular damage in a cryptorchid mouse model. PLoS One 2017; 12:e0177995. [PMID: 28542403 PMCID: PMC5436858 DOI: 10.1371/journal.pone.0177995] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/05/2017] [Indexed: 12/30/2022] Open
Abstract
Cryptorchidism or undescended testis (UDT) is a common congenital abnormality associated with increased risk for developing male infertility and testicular cancer. This study elucidated the effects of endogenous ghrelin or growth hormone secretagogue receptor (GHSR) deletion on mouse reproductive performance and evaluated the ability of ghrelin to prevent testicular damage in a surgical cryptorchid mouse model. Reciprocal matings with heterozygous/homozygous ghrelin and GHSR knockout mice were performed. Litter size and germ cell apoptosis were recorded and testicular histological evaluations were performed. Wild type and GHSR knockout adult mice were subjected to creation of unilateral surgical cryptorchidism that is a model of heat-induced germ cell death. All mice were randomly separated into two groups: treatment with ghrelin or with saline. To assess testicular damage, the following endpoints were evaluated: testis weight, seminiferous tubule diameter, percentage of seminiferous tubules with spermatids and with multinucleated giant cells. Our findings indicated that endogenous ghrelin deletion altered male fertility. Moreover, ghrelin treatment ameliorated the testicular weight changes caused by surgically induced cryptorchidism. Testicular histopathology revealed a significant preservation of spermatogenesis and seminiferous tubule diameter in the ghrelin-treated cryptorchid testes of GHSR KO mice, suggesting that this protective effect of ghrelin was mediated by an unknown mechanism. In conclusion, ghrelin therapy could be useful to suppress testicular damage induced by hyperthermia, and future investigations will focus on the underlying mechanisms by which ghrelin mitigates testicular damage.
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Affiliation(s)
- Enrica Bianchi
- Division of Urology, Rhode Island Hospital, Providence, RI, United States of America
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States of America
| | - Kim Boekelheide
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States of America
| | - Mark Sigman
- Division of Urology, Rhode Island Hospital, Providence, RI, United States of America
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States of America
| | - Susan J. Hall
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States of America
| | - Kathleen Hwang
- Division of Urology, Rhode Island Hospital, Providence, RI, United States of America
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, United States of America
- * E-mail:
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10
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Garcia JM, Chen JA, Guillory B, Donehower LA, Smith RG, Lamb DJ. Ghrelin Prevents Cisplatin-Induced Testicular Damage by Facilitating Repair of DNA Double Strand Breaks Through Activation of p53 in Mice. Biol Reprod 2015; 93:24. [PMID: 26019260 DOI: 10.1095/biolreprod.115.129759] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 05/22/2015] [Indexed: 12/20/2022] Open
Abstract
Cisplatin administration induces DNA damage resulting in germ cell apoptosis and subsequent testicular atrophy. Although 50 percent of male cancer patients receiving cisplatin-based chemotherapy develop long-term secondary infertility, medical treatment to prevent spermatogenic failure after chemotherapy is not available. Under normal conditions, testicular p53 promotes cell cycle arrest, which allows time for DNA repair and reshuffling during meiosis. However, its role in the setting of cisplatin-induced infertility has not been studied. Ghrelin administration ameliorates the spermatogenic failure that follows cisplatin administration in mice, but the mechanisms mediating these effects have not been well established. The aim of the current study was to characterize the mechanisms of ghrelin and p53 action in the testis after cisplatin-induced testicular damage. Here we show that cisplatin induces germ cell damage through inhibition of p53-dependent DNA repair mechanisms involving gamma-H2AX and ataxia telangiectasia mutated protein kinase. As a result, testicular weight and sperm count and motility were decreased with an associated increase in sperm DNA damage. Ghrelin administration prevented these sequelae by restoring the normal expression of gamma-H2AX, ataxia telangiectasia mutated, and p53, which in turn allows repair of DNA double stranded breaks. In conclusion, these findings indicate that ghrelin has the potential to prevent or diminish infertility caused by cisplatin and other chemotherapeutic agents by restoring p53-dependent DNA repair mechanisms.
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Affiliation(s)
- Jose M Garcia
- Division of Endocrinology, Diabetes and Metabolism, MCL, Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Department of Medicine, Baylor College of Medicine, Houston, Texas Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas Huffington Center on Aging, Baylor College of Medicine, Houston, Texas
| | - Ji-an Chen
- Division of Endocrinology, Diabetes and Metabolism, MCL, Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Department of Medicine, Baylor College of Medicine, Houston, Texas Department of Health Education, College of Preventive Medicine, Third Military Medical University, Chongqing, China
| | - Bobby Guillory
- Division of Endocrinology, Diabetes and Metabolism, MCL, Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. DeBakey Veterans Affairs Medical Center, Department of Medicine, Baylor College of Medicine, Houston, Texas Huffington Center on Aging, Baylor College of Medicine, Houston, Texas
| | - Lawrence A Donehower
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas
| | - Roy G Smith
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas Huffington Center on Aging, Baylor College of Medicine, Houston, Texas Department of Metabolism and Aging, The Scripps Research Institute Florida, Jupiter, Florida
| | - Dolores J Lamb
- Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas Scott Department of Urology, Baylor College of Medicine, Houston, Texas
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11
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Whirledge SD, Garcia JM, Smith RG, Lamb DJ. Ghrelin partially protects against cisplatin-induced male murine gonadal toxicity in a GHSR-1a-dependent manner. Biol Reprod 2015; 92:76. [PMID: 25631345 DOI: 10.1095/biolreprod.114.123570] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The chemotherapeutic drug cisplatin causes a number of dose-dependent side effects, including cachexia and testicular damage. Patients receiving a high cumulative dose of cisplatin may develop permanent azoospermia and subsequent infertility. Thus, the development of chemotherapeutic regimens with the optimal postsurvival quality of life (fertility) is of high importance. This study tested the hypothesis that ghrelin administration can prevent or minimize cisplatin-induced testicular damage and cachexia. Ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR-1a), are expressed and function in the testis. Targeted deletion of ghrelin, or its receptor, significantly increases the rate of cell death in the testis, suggesting a protective role. Intraperitoneal administration of vehicle, ghrelin, or cisplatin alone or in combination with ghrelin, in cycles of 9 or 18 days, to adult male C57Bl/6 mice was performed. Body weight was measured daily and testicular and epididymal weight, sperm density and motility, testicular histology, and testicular cell death were analyzed at the time of euthanization. Ghrelin coadministration decreased the severity of cisplatin-induced cachexia and gonadal toxicity. Body, testicular, and epididymal weights significantly increased as testicular cell death decreased with ghrelin coadministration. The widespread damage to the seminiferous epithelium induced by cisplatin administration was less severe in mice simultaneously treated with ghrelin. Furthermore, ghrelin diminished the deleterious effects of cisplatin on testis and body weight homeostasis in wild-type but not Ghsr(-/-) mice, showing that ghrelin's actions are mediated via GHSR. Ghrelin or more stable GHSR agonists potentially offer a novel therapeutic approach to minimize the testicular damage that occurs after gonadotoxin exposure.
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Affiliation(s)
- Shannon D Whirledge
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas
| | - Jose M Garcia
- Division of Endocrinology, Diabetes, and Metabolism, Michael E. DeBakey Veterans Affairs Medical Center, Baylor College of Medicine, Houston, Texas
| | - Roy G Smith
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida
| | - Dolores J Lamb
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas Scott Department of Urology, Baylor College of Medicine, Houston, Texas Center for Reproductive Medicine, Baylor College of Medicine, Houston, Texas
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12
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Abstract
After the discovery in 1996 of the GH secretagogue-receptor type-1a (GHS-R1a) as an orphan G-protein coupled receptor, many research groups attempted to identify the endogenous ligand. Finally, Kojima and colleagues successfully isolated the peptide ligand from rat stomach extracts, determined its structure, and named it ghrelin. The GHS-R1a is now accepted to be the ghrelin receptor. The existence of the ghrelin system has been demonstrated in many animal classes through biochemical and molecular biological strategies as well as through genome projects. Our work, focused on identifying the ghrelin receptor and its ligand ghrelin in laboratory animals, particularly nonmammalian vertebrates, has provided new insights into the molecular evolution of the ghrelin receptor. In mammals, it is assumed that the ghrelin receptor evolution is in line with the plate tectonics theory. In contrast, the evolution of the ghrelin receptor in nonmammalian vertebrates differs from that of mammals: multiplicity of the ghrelin receptor isoforms is observed in nonmammalian vertebrates only. This multiplicity is due to genome duplication and polyploidization events that particularly occurred in Teleostei. Furthermore, it is likely that the evolution of the ghrelin receptor is distinct from that of its ligand, ghrelin, because only one ghrelin isoform has been detected in all species examined so far. In this review, we summarize current knowledge related to the molecular evolution of the ghrelin receptor in mammalian and nonmammalian vertebrates.
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Affiliation(s)
- Hiroyuki Kaiya
- Department of BiochemistryNational Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
| | - Kenji Kangawa
- Department of BiochemistryNational Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
| | - Mikiya Miyazato
- Department of BiochemistryNational Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan
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13
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Moretti E, Vindigni C, Tripodi SA, Mazzi L, Nuti R, Figura N, Collodel G. Immunolocalisation of ghrelin and obestatin in human testis, seminal vesicles, prostate and spermatozoa. Andrologia 2013; 46:979-85. [PMID: 24147986 DOI: 10.1111/and.12183] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/11/2013] [Indexed: 12/18/2022] Open
Abstract
The role of ghrelin and obestatin in male reproduction has not completely been clarified. We explored ghrelin and obestatin localisation in the male reproductive system. Polyclonal antibodies anti-ghrelin and anti-obestatin were used to detect the expression of these hormones in human testis, prostate and seminal vesicles by immunocytochemistry, while in ejaculated and swim up selected spermatozoa by immunofluorescence. Sertoli cells were positive for both peptides and Leydig cells for ghrelin; germ cells were negative for both hormones. Mild signals for ghrelin and obestatin were observed in rete testis; efferent ductules were the most immune reactive region for both peptides. Epididymis was moderately positive for ghrelin; vas deferens and seminal vesicles showed intense obestatin and moderate ghrelin labelling; prostate tissue expressed obestatin alone. Ejaculated and selected spermatozoa were positive for both peptides in different head and tail regions. This study confirms ghrelin localisation in Leydig and Sertoli cells; the finding that ghrelin is expressed in rete testis, epididymis, vas deferens and seminal vesicles is novel, as well as the localisation of obestatin in almost all tracts of the male reproductive system. This research could offer insights for stimulating other studies, particularly on the role of obestatin in sperm physiology, which is still obscure.
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Affiliation(s)
- E Moretti
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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Michalakis K, Mintziori G, Kaprara A, Tarlatzis BC, Goulis DG. The complex interaction between obesity, metabolic syndrome and reproductive axis: a narrative review. Metabolism 2013; 62:457-78. [PMID: 22999785 DOI: 10.1016/j.metabol.2012.08.012] [Citation(s) in RCA: 202] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 08/13/2012] [Accepted: 08/18/2012] [Indexed: 12/16/2022]
Abstract
The aim of this narrative review is to provide current evidence for the interaction between obesity, metabolic syndrome (MS) and reproductive axis. Gonadotropin-releasing hormone (GnRH) pulses and, consequently, normal function of reproductive (hypothalamus-pituitary-gonadal) axis depend on normal energy balance, which presupposes sufficient food intake, reasonable energy consumption and average thermoregulatory costs. In case of an energy imbalance, reproductive dysfunction may occur. In young women, excessive leanness is accompanied by puberty delay, whereas premature puberty might be a manifestation of obesity. In a similar way, obesity in men affects fertility. Excess adipose tissue results in increased conversion of testosterone to estradiol, which may lead to secondary hypogonadism through reproductive axis suppression. Moreover, oxidative stress at the level of the testicular micro-environment may result in decreased spermatogenesis and sperm damage. Products of the adipocyte, such as leptin, adiponectin and resistin, and gut peptides, such as ghrelin, are considered to be crucial in the interaction between energy balance and reproduction. Finally, an indirect evidence for the interplay between MS and reproductive axis is the fact that when treating components of one, parameters of the other can be improved as well. These therapeutic interventions include lifestyle modifications, pharmacological agents, such as sex hormone replacement therapy, and surgical procedures. Although many issues remain unclear, the elucidation of the complex interaction between MS and reproductive axis will have obvious clinical implications in the therapeutic approach of both entities.
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Affiliation(s)
- Konstantinos Michalakis
- First Department of Internal Medicine, Laikon University Hospital, Athens University Medical School, Greece
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15
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Kaiya H, Kangawa K, Miyazato M. Ghrelin receptors in non-Mammalian vertebrates. Front Endocrinol (Lausanne) 2013; 4:81. [PMID: 23882259 PMCID: PMC3713435 DOI: 10.3389/fendo.2013.00081] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 06/20/2013] [Indexed: 11/13/2022] Open
Abstract
The growth hormone secretagogue-receptor (GHS-R) was discovered in humans and pigs in 1996. The endogenous ligand, ghrelin, was discovered 3 years later, in 1999, and our understanding of the physiological significance of the ghrelin system in vertebrates has grown steadily since then. Although the ghrelin system in non-mammalian vertebrates is a subject of great interest, protein sequence data for the receptor in non-mammalian vertebrates has been limited until recently, and related biological information has not been well organized. In this review, we summarize current information related to the ghrelin receptor in non-mammalian vertebrates.
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Affiliation(s)
- Hiroyuki Kaiya
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
- *Correspondence: Hiroyuki Kaiya, Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan e-mail:
| | - Kenji Kangawa
- National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - Mikiya Miyazato
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
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16
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Zhu CC, Zhang H, Zhang JS, Li Z, Zhao J, Li W, Zhang YQ. Inhibition of ghrelin signaling improves the reproductive phenotype of male ob/ob mouse. Fertil Steril 2012; 99:918-26. [PMID: 23232360 DOI: 10.1016/j.fertnstert.2012.11.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 11/12/2012] [Accepted: 11/12/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate whether ghrelin signaling is involved in the pathogenesis of male factor infertility induced by leptin deficiency. DESIGN Experimental study. SETTING University academic medical center. ANIMAL(S) Ten-week-old C57BL/6J mice and ob/ob mice. INTERVENTION(S) Western blotting, (quantitative) reverse transcription-polymerase chain reaction (qRT-PCR), immunohistochemistry, and in situ end labeling of fragmented DNA. MAIN OUTCOME MEASURE(S) Expression levels of ghrelin and its functional receptor growth hormone (GH) secretagogue receptor 1a (GHS-R1α) were examined by Western blotting and immunohistochemistry. Ob/ob mice were injected IP with specific GHS-R1α antagonist, and thereafter germ cell apoptosis and steroidogenic capability were assessed by TUNEL assay, (q) RT-PCR, and radioimmunoassay. RESULT(S) Expression of GHS-R1α and its endogenous ligand ghrelin was both up-regulated in ob/ob testis. Inhibition of the ghrelin pathway restored androgen synthesis, reduced germ cell apoptosis, and thereby resulted in improved sperm production in ob/ob mice. CONCLUSION(S) Ghrelin, as an antagonistic partner of leptin in the endocrinic/paracrine circuit, may be involved in the pathogenesis of male factor infertility induced by leptin deficiency.
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Affiliation(s)
- Chu-Chao Zhu
- Department of Human Anatomy and Histology and Embryology, the Fourth Military Medical University, Xian, People's Republic of China
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17
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Łukaszyk A, Kotwicka M, Jankowska A, Kasprzak A, Ruciński M, Sterzyńska K, Ziółkowska A, Sawiński P, Ruchala M. Expression of ghrelin receptor (GHSR-1a) in rat epididymal spermatozoa and the effects of its activation. Reprod Biol 2012; 12:293-300. [PMID: 23153700 DOI: 10.1016/j.repbio.2012.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 03/15/2012] [Indexed: 10/27/2022]
Abstract
In this study we demonstrated the expression of the ghrelin receptor GHSR-1a in rat spermatids and epididymal spermatozoa, as well as some effects of ghrelin on the spermatozoa in vitro. For the demonstration of GHSR-1a the immunocytochemical, immunofluorescence and Western blotting techniques were applied using three different types of antibodies. The response of spermatozoa to ghrelin was tested in a series of in vitro experiments and their effects were evaluated using confocal microscopy and flow cytometry. GHSR-1a protein was found as expressed in the Golgi and acrosomes of spermatids and acrosome regions or the head cell membrane of epididymal spermatozoa. The GHSR-1a expression in spermatozoa was also confirmed by Western blot. No differences were found in percentage of spermatozoa showing annexin-V binding and expression of active form caspase-3 between control and ghrelin-treated spermatozoa. This result may indicate no pro-apoptotic effects of ghrelin neither at 10(-9) nor 10(-6)mol/L concentration. Ghrelin (10(-6)mol/L) increased free intracellular calcium ion concentration in the rat spermatozoa. Moreover, stimulation with 10(-6)mol/L ghrelin increased, while 10(-4)mol/L ghrelin decreased the number of spermatozoa showing progressive motility. In conclusion, the expression of the GHSR-1a receptor in spermatozoa, as well as ghrelin influences on sperm motility and intracellular calcium ion concentration suggest that such biological effects of ghrelin may be produced under in vivo conditions.
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Affiliation(s)
- Andrzej Łukaszyk
- Department of Histology and Embryology, Poznań University of Medical Sciences, Poznań, Poland.
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18
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Fang F, Liu Y, Zhao X, Li Y, Zhang Y, Zhang X. The association between testicular ghrelin receptor mRNA and serum testosterone levels in immunocastrated boars. Anim Reprod Sci 2012; 135:62-7. [PMID: 23021962 DOI: 10.1016/j.anireprosci.2012.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 09/06/2012] [Accepted: 09/07/2012] [Indexed: 10/27/2022]
Abstract
Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has various functions. The expression of ghrelin and growth hormone secretagogue receptor type 1a (GHS-R1a) has been demonstrated in rat and human testis, and ghrelin also affects testosterone (T) secretion in vitro, suggesting a role for this molecule in the direct control of testis function. However, whether this signaling system is present in pig testis, and the association with serum T remains largely unexplored. In this study we investigated the relationship between serum T levels and ghrelin and GHS-R1a gene expression in the testes of intact and immunocastrated boars. Testicular tissue and serum samples were collected from seven intact boars and seven recombinant GnRH-I immunocastrated boars. GHS-R1a gene expression in the testis was higher in immunocastrated than intact boars (2.22 ± 0.71 vs. 0.53 ± 0.23; P<0.01). Mean serum T levels were markedly lower in immunocastrated than intact boars (0.40 ± 0.04 vs. 2.10 ± 0.94 ng/mL, P<0.01). Ghrelin gene expression in testis did not differ between both groups of boars. GHS-R1a gene expression was positively correlated with ghrelin gene expression (r = 0.68, P<0.001), but negatively correlated with serum T concentrations (r = -0.83, P<0.001). Overall, the existence of ghrelin and GHS-R1a gene expression in pig testis, and the increase in GHS-R1a gene expression in the testes and the inverse correlation with serum T in immunocastrated boars are highly suggestive of a role for ghrelin in the regulation of mammalian testicular function.
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Affiliation(s)
- Fugui Fang
- Department of Animal Veterinary Science, College of Animal Science and Technology, Anhui Agricultural University, Hefei, PR China
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19
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Abstract
Capsaicin (CAP), the active substance of red hot peppers, has been reported to stimulate development of the gonad. Ghrelin is an acylated polypeptide hormone that is secreted predominantly by endocrine cells of the stomach. There is evidence that ghrelin is involved in reproductive function. Ghrelin significantly inhibits testosterone secretion in a dose-dependent manner. We investigated the effect of CAP on ghrelin expression in testes of mice and on testosterone levels during pubertal and adult periods. We used a variety of morphometric, immunohistochemical and biochemical methods, and western blot analysis. The animals were divided into two age groups: puberty and adult. Control groups for both age groups were fed with standard diet and experimental groups were fed with a diet containing 0.02% CAP. Testes were collected quickly after sacrifice. After dehydration, the specimens were embedded in paraffin and 5 μm sections were cut, and Crossman's triple staining and immunohistochemical staining for ghrelin were applied. Immunohistochemical staining with ghrelin antibody for both age groups demonstrated immunoreaction especially in Leydig and Sertoli cells, but no reaction was observed in spermatogenic cells. Ghrelin immunoreaction was less intense in the experimental groups. Serum testosterone levels were increased in both experimental groups, especially in adults. More spermatocytes were observed in the experimental group compared to the control group. In both pubertal and adult experimental groups, the seminiferous epithelium was thick. CAP appears to enhance testicular cell proliferation and can affect the release of ghrelin and testosterone directly or indirectly.
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Affiliation(s)
- T Ilhan
- Department of Histology & Embryology, Faculty of Veterinary Medicine, University of Uludag, 16059 Görükle, Bursa, Turkey
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20
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Kheradmand A, Dezfoulian O, Alirezaei M. Ghrelin regulates Bax and PCNA but not Bcl-2 expressions following scrotal hyperthermia in the rat. Tissue Cell 2012; 44:308-15. [PMID: 22658447 DOI: 10.1016/j.tice.2012.04.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 04/23/2012] [Accepted: 04/29/2012] [Indexed: 12/17/2022]
Abstract
More recently, we have reported the beneficial effects of ghrelin in improvement of histopathological features of the rat testis following local heat exposure. However, the exact mechanism and the precise role of apoptosis- and proliferation-specific proteins in this regeneration process remained to be explored. Thus, thirty adult male Wistar rats were allotted for the experiment and subdivided equally into three groups: control-saline (CS), heat-saline (HS) and heat-ghrelin (HG). The scrota of HS and HG groups were immersed once in water bath at 43°C for 15 min. HG animals received 2 nmol of ghrelin subcutaneously immediately after heating every other day until day 60 and the other groups were given physiological saline using the same method. The testes of all groups were taken after rat killing on days 30 and 60 after heat treatment for immunocytochemical detection of pro-apoptotic factor Bax, anti-apoptotic protein Bcl-2 and proliferation-associated peptide PCNA in the germ cells. Ghrelin could significantly suppress the Bax expression in spermatocytes compared to the HS group at day 30 (P<0.05). Likewise, the mean percentages of spermatogonia containing Bax substance were lower in ghrelin-exposed animals, however the differences were not statistically significant. There were immunoreactive cells against Bcl-2 in each germ cell neither in the control nor in the heated animals of experimental groups. In contrast, the number of PCNA immunolabeling cells were higher in HG group in compared to HS or CS animals on both experimental days (P<0.001). Down-regulation of Bax expression concurrent with overexpression of PCNA in HG group indicates the ability of ghrelin in acceleration of testicular germ cells regeneration following heat stress. These findings indicate that ghrelin may be used as a novel and efficient antioxidant agent to induce resumption of spermatogenesis upon environmental heat exposure.
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Affiliation(s)
- Arash Kheradmand
- Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad, Iran.
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21
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Stengel A, Taché Y. Ghrelin - a pleiotropic hormone secreted from endocrine x/a-like cells of the stomach. Front Neurosci 2012; 6:24. [PMID: 22355282 PMCID: PMC3280431 DOI: 10.3389/fnins.2012.00024] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 01/29/2012] [Indexed: 12/13/2022] Open
Abstract
The gastric X/A-like endocrine cell receives growing attention due to its peptide products with ghrelin being the best characterized. This peptide hormone was identified a decade ago as a stimulator of food intake and to date remains the only known peripherally produced and centrally acting orexigenic hormone. In addition, subsequent studies identified numerous other functions of this peptide including the stimulation of gastrointestinal motility, the maintenance of energy homeostasis and an impact on reproduction. Moreover, ghrelin is also involved in the response to stress and assumed to play a role in coping functions and exert a modulatory action on immune pathways. Our knowledge on the regulation of ghrelin has markedly advanced during the past years by the identification of the ghrelin acylating enzyme, ghrelin-O-acyltransferase, and by the description of changes in expression, activation, and release under different metabolic as well as physically and psychically challenging conditions. However, our insight on regulatory processes of ghrelin at the cellular and subcellular levels is still very limited and warrants further investigation.
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Affiliation(s)
- Andreas Stengel
- Division Psychosomatic Medicine and Psychotherapy, Department of Medicine, Charité - Universitätsmedizin Berlin Berlin, Germany
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22
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Puechagut PB, Martini AC, Stutz G, Santillán ME, Luque EM, Fiol de Cuneo M, Ruiz RD, Vincenti LM. Reproductive performance and fertility in male and female adult mice chronically treated with hexarelin. Reprod Fertil Dev 2012; 24:451-60. [DOI: 10.1071/rd11009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 07/06/2011] [Indexed: 01/08/2023] Open
Abstract
Hexarelin (HEXr), a synthetic ghrelin analogue, has been associated with modifications of reproductive physiology. In previous studies of adult mice, we detected that HEXr induced significantly reduced ovulation rate and significant correlation coefficients between sexual maturation and corporal weight in offspring. In this study, we investigated the effects of chronic HEXr administration on sperm concentration and functional activity, oestrous cyclicity and pregnancy index, in addition to the number of fetuses and its correlation with the number of corpora lutea. Adult Albino swiss mice were injected (sc) daily with HEXr: 100 μg kg–1 day–1 (HEXr D1) or 200 μg kg–1 day–1 (HEXr D2) for 53 days in males and 30 days in females. We detected a significantly decreased ratio in the number of fetuses per corpora lutea in females treated with HEXr D2 for 30 days before mating and during the first 6 days of pregnancy, in addition to a downward trend in the pregnancy index and percentage of females impregnated by each male treated with both doses of the analogue. Although we did not find any significant effect on additional parameters evaluated in both genders, we propose certain effects of HEXr on the implantation process and/or early development of embryos and over the in vivo reproductive capability of males.
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23
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Muccioli G, Lorenzi T, Lorenzi M, Ghè C, Arnoletti E, Raso GM, Castellucci M, Gualillo O, Meli R. Beyond the metabolic role of ghrelin: a new player in the regulation of reproductive function. Peptides 2011; 32:2514-21. [PMID: 22074955 DOI: 10.1016/j.peptides.2011.10.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 10/23/2011] [Accepted: 10/23/2011] [Indexed: 11/30/2022]
Abstract
Ghrelin is a gastric peptide, discovered by Kojima et al. (1999) [55] as a result of the search for an endogenous ligand interacting with the "orphan receptor" GHS-R1a (growth hormone secretagogue receptor type 1a). Ghrelin is composed of 28 aminoacids and is produced mostly by specific cells of the stomach, by the hypothalamus and hypophysis, even if its presence, as well as that of its receptors, has been demonstrated in many other tissues, not least in gonads. Ghrelin potently stimulates GH release and participates in the regulation of energy homeostasis, increasing food intake, decreasing energy output and exerting a lipogenetic effect. Furthermore, ghrelin influences the secretion and motility of the gastrointestinal tract, especially of the stomach, and, above all, profoundly affects pancreatic functions. Despite of these previously envisaged activities, it has recently been hypothesized that ghrelin regulates several aspects of reproductive physiology and pathology. In conclusion, ghrelin not only cooperates with other neuroendocrine factors, such as leptin, in the modulation of energy homeostasis, but also has a crucial role in the regulation of the hypothalamic-pituitary gonadal axis. In the current review we summarize the main targets of this gastric peptide, especially focusing on the reproductive system.
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Affiliation(s)
- Giampiero Muccioli
- Department of Drug Science and Technology, Division of Medical Pharmacology, University of Torino, Via P. Giuria 13, 10125 Torino, Italy
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Repaci A, Gambineri A, Pagotto U, Pasquali R. Ghrelin and reproductive disorders. Mol Cell Endocrinol 2011; 340:70-9. [PMID: 21453749 DOI: 10.1016/j.mce.2011.02.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 02/26/2011] [Accepted: 02/26/2011] [Indexed: 12/13/2022]
Abstract
Ghrelin is an important factor involved in most of the metabolic and hormonal signals which adapt the reproductive functions in conditions of altered energy balance. Moreover, the coordinated role of leptin and ghrelin appears in fact to have a specific role in the regulation of puberty. Systemic action of ghrelin on the reproductive axis involves the control of the hypothalamic-pituitary-gondal axis. In addition, it has been shown that ghrelin may directly act at a gonadal level in both females and males. Available data also demonstrate that sex steroid hormones and gonadotropins may in turn regulate the gonadal effect of ghrelin, as documented by studies performed in females with the polycystic ovary syndrome and in hypogonadal men. Notably, recent studies also confirm a potentially important role for ghrelin in fetal and neonatal energy balance, and specifically in allowing fetal adaptation to an adverse intrauterine environment.
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Affiliation(s)
- Andrea Repaci
- St. Orsola-Malpighi Hospital, University Alma Mater Studiorum, Bologna, Italy
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Ghrelin in female and male reproduction. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010. [PMID: 20700403 PMCID: PMC2911616 DOI: 10.1155/2010/158102] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 12/23/2009] [Accepted: 01/09/2010] [Indexed: 11/23/2022]
Abstract
Ghrelin and one of its functional receptors, GHS-R1a (Growth Hormone Secretagogue Receptor 1a), were firstly studied about 15 years. Ghrelin is a multifunctional peptide hormone that affects several biological functions including food intake, glucose release, cell proliferation… Ghrelin and GHS-R1a are expressed in key cells of both male and female reproductive organs in several species including fishes, birds, and mammals suggesting a well-conserved signal through the evolution and a role in the control of fertility. Ghrelin could be a component of the complex series of nutrient sensors such as adipokines, and nuclear receptors, which regulate reproduction in function of the energy stores. The objective of this paper was to report the available information about the ghrelin system and its role at the level of the hypothalamic-pituitary-gonadal axis in both sexes.
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Nurmio M, Tena-Sempere M, Toppari J. Orexins and the regulation of the hypothalamic-pituitary-testicular axis. Acta Physiol (Oxf) 2010; 198:349-54. [PMID: 19476455 DOI: 10.1111/j.1748-1716.2009.02006.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Orexins (OX), OX-A and OX-B, were initially identified as hypothalamic neuropeptides primarily involved in the control of food intake and states of arousal. Thereafter, orexins have been substantiated as putative pleiotropic regulators of a wide diversity of biological systems, including different neuroendocrine axes. Among the latter, compelling experimental evidence has recently been documented that orexins, mainly OX-A, may act at different levels of the hypothalamic-pituitary-gonadal (HPG) axis to modulate reproductive function. These actions are likely to include regulatory effects on the hypothalamic centres governing the HPG axis, as well as direct actions at the gonadal level. We review herein the experimental evidence, gathered in recent years, supporting a reproductive 'facet' of orexins, with special emphasis on our current knowledge of their patterns of expression and potential functional roles in the testis. Overall, the available data strongly suggest that, by acting at different levels of the HPG axis, orexins may operate as putative neuroendocrine and autocrine/paracrine regulators of gonadal function.
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Affiliation(s)
- M Nurmio
- Department of Physiology, University of Turku, Turku, Finland
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Immunohistochemical and hybridocytochemical study on ghrelin signalling in the rat seminiferous epithelium. Folia Histochem Cytobiol 2010; 47:415-23. [PMID: 20164026 DOI: 10.2478/v10042-009-0097-9] [Citation(s) in RCA: 1] [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 results of presented study demonstrate expression of ghrelin, its functional receptor GHSR-1a and their genes in spermatogenic cells of rat testis suggesting their functioning within seminiferous epithelium. The immunohistochemical and hybrydocytochemical expression, of proteins and transcripts, was estimated taking into account the cycle of seminiferous epithelium and phases of spermatogenesis. Both transcripts and ghrelin was found to show nuclear expression and scarcely cytoplasmic. Expression of genes for ghrelin and GHSR-1a was shown in early spermatocytes and round spermatids representing transcriptional phases of meiosis and spermiogenesis. Ghrelin was evidenced to show nuclear expression in two stage-specific windows, in late spermatogonia, in spermatocytes up to early pachytenes, and again in spermatids of acrosome and early maturation phase of spermiogenesis. In late pachytenes, secondary spermatocytes, round spermatids, maturing spermatids and spermatozoa the reaction is lacking. With two types of antibodies against the GHSR-1a used the two different patterns of immunostaining was evidenced suggesting two isoforms of GHSR-1a. The first evidenced GHSR-1a in cytoplasm of spermatocytes, cell membrane and acrosomes of spermatids, Sertoli cell processes and heads of spermatozoa. With second type of antibodies the immunostaining marks all steps of evolution of acrosome in spermatids. It is believed that site of ghrelin expression in seminiferous epithelium may indicate its role in local regulations, not excepting the intracellular signalling. Immunostaining pattern for GHSR-1a seems to suggest both its participation in the cross-talk among the cells and also process of furnishing gametes with GHSR-1a for its response to ghrelin in seminal plasma or female reproductive tract.
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Bian ZH, Zhang J, Ding XL, Zhang B, Wang ZJ, Lu CC, Song L, Wang SL, Wang XR. Localization of epididymal protease inhibitor in adult rat and its transcription profile in testis during postnatal development. Asian J Androl 2009; 11:731-9. [PMID: 19801999 DOI: 10.1038/aja.2009.66] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
To investigate the expression pattern of rat Eppin (epididymal protease inhibitor; official symbol Spinlw1), we detected mRNA transcripts and subsequent protein translation of Eppin in several sorts of tissues by RT-PCR and western blotting. Then immunohistochemistry was performed for more detailed observation. The testicular transcription level was monitored by real-time PCR throughout postnatal development. We found that rat Eppin was specifically expressed in the testis and epididymis. The testicular transcription was slight in neonatal (1-day) and infantile stages (5-, 7- and 10-day). It increased sharply thereafter, with maximum expression level (about 38-fold compared with that of 1-day old rat) detected in prepubertal stage (15-day). Then a slightly declined but stable level (about 20-fold compared with that of 1-day old rat) was kept in pubertal-early adult (30-day) and adult (60-day) stages of postnatal maturation. In the adult rat, EPPIN protein was mainly localized in the elongated spermatids and epididymal epithelial cells. Sperm in the epididymal duct were all covered with EPPIN and its level kept constant during incubation under conditions used to achieve capacitation. Its stage-specific expression in the testis suggests that EPPIN may be important during spermatogenesis especially for the spermatid elongation. The abundant production of epididymal EPPIN indicated indirectly that it might play a role in the function of the epididymis.
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Affiliation(s)
- Zeng-Hui Bian
- Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
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Dong XY, Xu J, Tang SQ, Li HY, Jiang QY, Zou XT. Ghrelin and its biological effects on pigs. Peptides 2009; 30:1203-11. [PMID: 19463757 DOI: 10.1016/j.peptides.2009.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 03/01/2009] [Accepted: 03/02/2009] [Indexed: 12/23/2022]
Abstract
Ghrelin is a 28 amino acid peptide, which produces its marked effects through binding to the endogenous ligand of the growth hormone secretagogue receptor (GHS-R). Based on the contemporary literatures, it was shown that ghrelin was involved in a series of biological functions including regulation of food intake, body weight, gastrointestinal (GI) motility, hormone secretion, glucose release, cardiovascular functions, enzyme release, cell proliferation and reproduction in pigs through binding to GHS-R 1a or unidentified receptors. It was also observed that ghrelin induced adipocyte and hepatocyte proliferation of primary cultured piglet. In this paper, recent research on ghrelin structure, distribution, GHS-R receptor, biological functions and its regulatory mechanisms for pigs are presented.
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Affiliation(s)
- Xiao-Ying Dong
- College of Yingdong Bioengineering, Shaoguan University, Zhenjiang District, Shaoguan, Guangdong, China
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Lorenzi T, Meli R, Marzioni D, Morroni M, Baragli A, Castellucci M, Gualillo O, Muccioli G. Ghrelin: a metabolic signal affecting the reproductive system. Cytokine Growth Factor Rev 2009; 20:137-52. [DOI: 10.1016/j.cytogfr.2009.02.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Ghrelin is dispensable for embryonic pancreatic islet development and differentiation. ACTA ACUST UNITED AC 2009; 157:51-6. [PMID: 19268691 DOI: 10.1016/j.regpep.2009.02.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Accepted: 02/17/2009] [Indexed: 11/20/2022]
Abstract
Ghrelin is a peptide hormone that has been implicated in the regulation of food intake and energy homeostasis. Ghrelin is predominantly produced in the stomach, but is also expressed in many other tissues where its functions are not well characterized. In the rodent and human pancreas, ghrelin levels peak at late gestation and gradually decline postnatally. Several studies have suggested that ghrelin regulates beta cell function during embryonic development and in the adult. In addition, in a number of mouse models, ghrelin cells appear to replace insulin- and glucagon-producing cells in the islet. In this analysis, we investigated whether the absence or overexpression of ghrelin influenced the development and differentiation of the pancreatic islet during embryonic development. These studies revealed that ghrelin is dispensable for normal pancreas development during gestation. Conversely, we demonstrated that elevated ghrelin in the Nkx2.2 null islets is not responsible for the absence of insulin- and glucagon-producing cells. Finally, we have also determined that in the absence of insulin, ghrelin cells form in their normal numbers and ghrelin is expressed at wild type levels.
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Tena-Sempere M. Ghrelin as a pleotrophic modulator of gonadal function and reproduction. ACTA ACUST UNITED AC 2008; 4:666-74. [DOI: 10.1038/ncpendmet1003] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 09/29/2008] [Indexed: 11/09/2022]
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Duran C, Yonem A, Ustun I, Ozcan O, Ipcioglu OM, Basekim CC. Plasma ghrelin levels in males with idiopathic hypogonadotropic hypogonadism. Endocrine 2008; 34:81-6. [PMID: 18946744 DOI: 10.1007/s12020-008-9102-x] [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: 07/14/2008] [Revised: 08/28/2008] [Accepted: 09/08/2008] [Indexed: 11/27/2022]
Abstract
It has recently been shown that ghrelin is a pleitropic modulator with effects on diverse biological functions, such as energy homeostasis and reproduction. In this study, ghrelin levels and its relationship between metabolic and biochemical parameters were investigated in male subjects with idiopathic hypogonadotropic hypogonadism (IHH). Patients in the study were composed of 33 men with IHH, and controls were composed of 36 healthy age-matched men. The patients' group had significantly higher waist/hip ratio (WHR), and lower testis volume, luteinizing hormone (LH), follicle stimuling hormone (FSH) and total testosterone (TT) levels when compared with controls. Plasma total ghrelin levels were significantly lower in patients than in controls (96.4 +/- 29.1 ng/ml vs. 146.1 +/- 28.9 ng/ml, P < 0.001, respectively). No correlation of ghrelin was found with body mass index, waist/hip ratio, homeostasis model assessment insulin resistance index, testis volume, LH, FSH and TT levels in both patients and controls. The present study showed that ghrelin levels were significantly lower in men with IHH than in controls. However, further studies are needed to better understand the relationships between ghrelin, and metabolic and reproductive systems.
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Affiliation(s)
- Cevdet Duran
- Division of Endocrinology, Metabolism and Internal Medicine, Konya Education and Research Hospital, Meram, Konya, Turkey.
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Panidis D, Goulis DG, Katsikis I, Koliakos G, Georgopoulos NA, Diamanti-Kandarakis E. Serum and seminal plasma ghrelin levels in men with normospermia and dyspermia. Gynecol Endocrinol 2008; 24:320-5. [PMID: 18584411 DOI: 10.1080/09513590802002551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
AIMS To investigate the existence of ghrelin in seminal plasma and the levels of serum ghrelin in men with normospermia and dyspermia. SUBJECTS AND METHODS Ninety-eight men were classified into three groups: Group 1, men with normospermia and proven fertility (n = 26); Group 2, men with idiopathic oligo-astheno-teratozoospermia (n = 62); and Group 3, men with idiopathic azoospermia (n = 10). Spermiograms and determination of ghrelin in serum and seminal plasma were performed in all men. RESULTS Ghrelin was present in the seminal plasma of men from all groups at a concentration of 27%, 18% and 30% of the corresponding serum levels (mean +/- standard error: Group 1, 127.7 +/- 14.7 vs. 468.3 +/- 35.5 pmol/l, p = 0.003; Group 2, 117.0 +/- 10.1 vs. 637.0 +/- 29.3 pmol/l, p < 0.001; Group 3, 166.2 +/- 32.5 vs. 557.7 +/- 25.4 pmol/l, p = 0.068). When Group 1 men were compared with men from Groups 2 and 3 combined, there were no significant differences in serum (mean +/- standard error: 468.3 +/- 35.5 vs. 628.0 +/- 26.4 pmol/l, p = not significant) or seminal plasma ghrelin (mean +/- standard error: 127.7 +/- 14.7 vs. 123.9 +/- 9.9 pmol/l, p = not significant). In the total group of studied men (Groups 1 to 3), serum ghrelin was positively correlated with semen volume (r = 0.309, p = 0.037), whereas seminal plasma ghrelin was negatively correlated with age (r = -0.268, p = 0.008) and semen volume (r = -0.385, p < 0.000). CONCLUSIONS Ghrelin is present in human seminal plasma at lower levels than in serum. There is no difference in seminal plasma ghrelin levels between men with normospermia and dyspermia.
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Affiliation(s)
- Dimitrios Panidis
- Division of Endocrinology and Human Reproduction, Second Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Tena-Sempere M. Ghrelin and reproduction: ghrelin as novel regulator of the gonadotropic axis. VITAMINS AND HORMONES 2008; 77:285-300. [PMID: 17983861 DOI: 10.1016/s0083-6729(06)77012-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Identification of ghrelin in late 1999, as the endogenous ligand of the growth hormone secretagogue receptor (GHSR), opened up a new era in our understanding of the regulatory mechanisms of several neuroendocrine systems, including growth and energy homeostasis. Based on similarities with other endocrine integrators and its proposed role as signal for energy insufficiency, it appeared tempting to hypothesize that ghrelin might also operate as regulator of reproductive function. Yet, contrary to other of its biological actions the reproductive "dimension" of ghrelin has remained largely unexplored. Nonetheless, experimental evidence, coming mostly from animal studies, have been gathered during the last years suggesting that ghrelin may actually function as a metabolic modulator of the gonadotropic axis, with predominant inhibitory effects in line with its role as signal of energy deficit. These effects likely include inhibition of luteinizing hormone (LH) secretion (which has been reported in different species and developmental stages), as well as partial suppression of normal puberty onset. In addition, expression and/or direct gonadal actions of ghrelin have been reported in the human, rat, and chicken. Altogether, those findings document a novel reproductive facet of ghrelin, which may cooperate with other neuroendocrine integrators, as leptin, in the joint control of energy balance and reproduction.
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Affiliation(s)
- Manuel Tena-Sempere
- Physiology Section, Department of Cell Biology, Physiology and Immunology, University of Córdoba, 14004, Córdoba, Spain
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36
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Lai KC, Cheng CHK, Leung PS. The ghrelin system in acinar cells: localization, expression, and regulation in the exocrine pancreas. Pancreas 2007; 35:e1-8. [PMID: 17895831 DOI: 10.1097/mpa.0b0013e31812eee3e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVES Ghrelin and its receptor are expressed abundantly in the stomach and pituitary. Recently, a ghrelin system, consisting of both ligand and receptor, has also been found to exist in the endocrine cells of pancreatic islets. This ghrelin system may play a role in regulating insulin secretion and glucose homeostasis. The aim of the present study was to investigate whether a functional ghrelin system also exists in the exocrine pancreas. METHODS Precise localization and expression of ghrelin and its receptor in rat pancreatic acinar cells were examined by immunocytochemistry and Western blot, whereas messenger RNA levels were examined by semiquantitative reverse transcription-polymerase chain reaction. The roles of physiological and pathophysiological conditions, such as gastric acid inhibition, starvation, and acute pancreatitis, in regulation of ghrelin and its receptor were also examined. RESULTS Both ghrelin and its receptor were detected, at both protein and messenger RNA levels, in the acinar cells of the exocrine pancreas. Ghrelin receptor expression was up-regulated by gastric acid inhibition and down-regulated by acute pancreatitis, whereas levels remained unchanged after food deprivation. In contrast, ghrelin expression did not exhibit significant changes in any condition. CONCLUSIONS Our data indicate that a ghrelin system exists in the acinar cells of the exocrine pancreas. This system is subject to regulation by physiological and pathophysiological stimuli and may thus regulate exocrine functions by paracrine and/or autocrine mechanisms.
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Affiliation(s)
- Kit Ching Lai
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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37
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Rocha-Sousa A, Henriques-Coelho T, Leite-Moreira AF. Potential role of the growth hormone secretagogues in clinical practice. Expert Opin Ther Pat 2007. [DOI: 10.1517/13543776.17.8.909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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García MC, López M, Alvarez CV, Casanueva F, Tena-Sempere M, Diéguez C. Role of ghrelin in reproduction. Reproduction 2007; 133:531-40. [PMID: 17379649 DOI: 10.1530/rep-06-0249] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Ghrelin, the endogenous ligand of GH secretagogue receptor type 1a, has emerged as a pleiotropic modulator of diverse biological functions, including energy homeostasis and, lately reproduction. Here, we review recent reports evaluating the reproductive effects and sites of action of ghrelin, with particular emphasis regarding its role as a molecule integrating reproductive function and energy status. Data gleaned from rodent studies clearly show that besides having direct gonadal effects, ghrelin may participate in the regulation of gonadotropin secretion and it may influence the timing of puberty. In addition, experimental data showing that ghrelin and/or its receptor are expressed in normal human ovary and testis as well as in human ovarian and testicular tumors raise the possibility that the ghrelin system may be involved in the control of cell proliferation in these tumors. We propose that ghrelin either acting as an endocrine and/or paracrine signal may play a major role in the endocrine network that integrates energy balance and reproduction.
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Affiliation(s)
- María C García
- Department of Physiology, School of Medicine, University of Santiago de Compostela, R/San Francisco s/n, 15782 Santiago de Compostela (A Coruña), Spain
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Fernández-Fernández R, Tena-Sempere M, Roa J, Castellano JM, Navarro VM, Aguilar E, Pinilla L. Direct stimulatory effect of ghrelin on pituitary release of LH through a nitric oxide-dependent mechanism that is modulated by estrogen. Reproduction 2007; 133:1223-32. [PMID: 17636176 DOI: 10.1530/rep-06-0227] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Ghrelin, a gut peptide with key actions on food intake and GH secretion, has been recently recognized as potential regulator of reproductive function. Thus, in adult female rats, ghrelin has been proven to modulate GnRH/LH secretion, with predominant inhibitory effectsin vivo. We analyze herein potential direct pituitary effects of ghrelin on basal and GnRH-stimulated gonadotropin secretion in prepubertal female rats, and its interplay with ovarian inputs, nitric oxide (NO), and hypothalamic differentiation. In the experimental setting, pituitaries from intact and ovariectomized prepubertal female rats were challenged with ghrelinin vitroand LH secretion was monitored. Our results demonstrate that 1) ghrelin consistently stimulatedin vitropituitary LH secretion under different experimental conditions; 2) the sensitivity to ghrelin, expressed either as the minimal effective dose or the amplitude of the LH response, was modulated by ovarian inputs; 3) the blockade of estrogen action significantly augmented the stimulatory effect of ghrelin; 4) the stimulatory effect of ghrelin on LH secretion required proper NO synthesis; and 5) the ability of ghrelin to elicit LH secretionin vitrowas preserved after alteration (masculinization) of brain sexual differentiation. Overall, our present data reinforce the concept that ghrelin participates in the control of LH secretion, with potential stimulatory actions at the pituitary level that require the presence of NO and are modulated by ovarian signals.
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Tena-Sempere M, Barreiro ML, Lage M, Dieguez C, Casanueva FF. Role of leptin and ghrelin in the regulation of gonadal function. Expert Rev Endocrinol Metab 2007; 2:239-249. [PMID: 30754186 DOI: 10.1586/17446651.2.2.239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Gonadal development and function is sustained by the complex interaction of an array of regulatory signals that operate directly on the gonads and/or indirectly via modulation of gonadotropin secretion. During the last decade, different factors primarily involved in the control of food intake and energy balance have been demonstrated as putative modulators of different elements of the reproductive axis, including the gonads, thus helping to define the neuroendocrine basis for the link between body energy stores and fertility. These factors include not only the adipocyte-derived hormone leptin, which is indispensable for proper energy balance and reproduction, but also a number of neuropeptides and hormones of central and peripheral origin. In the latter, growing evidence strongly suggests the involvement of the stomach-secreted peptide ghrelin in the control of several aspects of gonadal function. Interestingly, leptin and ghrelin have been proposed as reciprocally related regulators of energy homeostasis; however, their potential interplay in the control of reproduction remains ill defined. This work will summarize the most salient findings concerning the potential roles of leptin and ghrelin in the functional control of the gonads. In addition, open issues regarding the reproductive facets of these metabolic signals will be highlighted. Overall, the authors propose that through complementary or antagonistic actions, leptin and ghrelin may jointly cooperate to modulate a wide set of reproductive functions, thereby contributing to the physiologic integration of energy balance and reproduction.
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Affiliation(s)
- M Tena-Sempere
- a University of Córdoba, Physiology Section, Department of Cell Biology, Physiology & Immunology, 14004 Córdoba, Spain.
| | - M L Barreiro
- b University of Córdoba, Physiology Section, Department of Cell Biology, Physiology & Immunology, 14004 Córdoba, Spain.
| | - M Lage
- c University of Santiago de Compostela, Department of Medicine, Faculty of Medicine, Complejo Hospitalario Universitario de Santiago, 15705 Santiago de Compostela, Spain.
| | - C Dieguez
- d University of Santiago de Compostela, Department of Physiology, Faculty of Medicine, Complejo Hospitalario Universitario de Santiago, 15705 Santiago de Compostela, Spain.
| | - F F Casanueva
- e University of Santiago de Compostela, Department of Medicine, Faculty of Medicine, Complejo Hospitalario Universitario de Santiago, 15705 Santiago de Compostela, Spain.
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41
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Tena-Sempere M. Roles of ghrelin and leptin in the control of reproductive function. Neuroendocrinology 2007; 86:229-41. [PMID: 17851226 DOI: 10.1159/000108410] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2006] [Accepted: 11/27/2006] [Indexed: 01/17/2023]
Abstract
Reproductive function in mammals, defined as the capacity to generate viable male and female gametes, and to support pregnancy and lactation selectively in the female, is sensitive to the metabolic state of the organism. This contention, long assumed on the basis of intuitive knowledge, became formulated on a scientific basis only recently, with the identification of a number of neuroendocrine signals which crucially participate in the joint control of energy balance and reproduction. A paradigmatic example in this context is the adipocyte-derived hormone, leptin; a satiety factor which signals the amount of body energy (fat) stores not only to the circuits controlling food intake but also to a number of neuroendocrine axes, including the reproductive system. More recently, the reproductive dimension of another metabolic hormone, namely the orexigenic stomach-secreted peptide, ghrelin, has been disclosed by observations on its putative roles in the control of gonadal function and gonadotropin secretion. Of note, leptin and ghrelin have been proposed to act as reciprocal regulators of energy homeostasis. However, their potential interplay in the control of reproduction remains largely unexplored. Based on the comparison of the biological actions of leptin and ghrelin at different levels of the hypothalamic-pituitary-gonadal axis, reviewed in detail herein, we propose that, through concurrent or antagonistic actions, the leptin-ghrelin pair is likely to operate also as modulator of different reproductive functions, thereby contributing to the physiological integration of reproduction and energy balance.
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Affiliation(s)
- Manuel Tena-Sempere
- Physiology Section, Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain.
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42
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Pasquali R. Obesity and androgens: facts and perspectives. Fertil Steril 2006; 85:1319-40. [PMID: 16647374 DOI: 10.1016/j.fertnstert.2005.10.054] [Citation(s) in RCA: 294] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2005] [Revised: 10/26/2005] [Accepted: 10/26/2005] [Indexed: 01/22/2023]
Abstract
OBJECTIVE This review discusses androgen status in male and female obesity, according to their specific phenotype, and the main mechanisms responsible. DESIGN Published data in the literature of the last 20 years represented the basis of most of the data and concepts incorporated in the review. RESULT(S) Obesity is associated with profound alterations in androgen secretion, transport, metabolism, and action, according to a dichotomous behavior depending on sex. Obese men are characterized by a progressive decrease of testosterone levels with increasing body weight, whereas obese women, particularly those with the abdominal phenotype, tend to develop a condition of functional hyperandrogenism. Reduced sex hormone-binding globulin synthesis and circulating blood levels represent the sole common mechanism which is responsible in both sexes. Among other still partially undefined factors, mechanisms potentially responsible for the sex dichotomy in androgen levels involve specific alterations of gonadotropin secretion, estrogens, the hypothalamic-pituitary-adrenal axis, leptin, androgen receptors, specific steroidogenic enzymes in the peripheral tissues, and, possibly, ghrelin. In both sexes, androgens play an important role in determining the sex-dependent pattern of body fat distribution. Moreover there are theoretical possibilities that low testosterone in men and high free testosterone fraction in women may play a role in the development of the metabolic syndrome. This is exemplified by the well defined association between obesity and other features of the metabolic syndrome in women with polycystic ovary syndrome and in hypogonadal men. The effects of androgen and antiandrogens in obese men and women also represent arguments in favor of this association. CONCLUSION(S) Given the fundamental role of sex hormones in the regulation of body composition, fuel homeostasis, and reproduction in humans, more emphasis should be placed on the potential role of androgen dysregulation in the pathophysiology of different obesity phenotypes and the metabolic syndrome.
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Affiliation(s)
- Renato Pasquali
- Division of Endocrinology, Department of Internal Medicine, Sant'Orsola-Malpighi Hospital, University Alma Mater Studiorum, Bologna, Italy.
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Pulman KJ, Fry WM, Cottrell GT, Ferguson AV. The subfornical organ: a central target for circulating feeding signals. J Neurosci 2006; 26:2022-30. [PMID: 16481435 PMCID: PMC6674925 DOI: 10.1523/jneurosci.3218-05.2006] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 01/05/2005] [Accepted: 01/06/2006] [Indexed: 11/21/2022] Open
Abstract
The mechanisms through which circulating ghrelin relays hunger signals to the CNS are not yet fully understood. In this study, we have examined the potential role of the subfornical organ (SFO), a circumventricular structure that lacks the normal blood-brain barrier, as a CNS site in which ghrelin acts to influence the hypothalamic centers controlling food intake. We report that ghrelin increased intracellular calcium concentrations in 28% (12 of 43) of dissociated SFO neurons and that the SFO expresses mRNA for the growth hormone secretagogue receptor. Whole-cell patch recordings from SFO neurons demonstrated that in 29% (9 of 31) of neurons tested ghrelin induced a mean depolarization of 7.4 +/- 0.69 mV, accompanied by an increase in action potential frequency. Voltage-clamp recordings revealed that ghrelin activates a putative nonselective cationic conductance. Previous reports that the satiety signal amylin exerts similar excitatory effects on SFO neurons led us to examine whether these two peptides influence different subpopulations of SFO neurons. Concentration-dependent depolarizing effects of amylin were observed in 59% (28 of 47) of SFO neurons (mean depolarization, 8.32 +/- 0.60 mV). In contrast to ghrelin, voltage-clamp recordings suggest that amylin influences a voltage-dependent current activated at depolarized potentials. We tested single SFO neurons with both peptides and identified cells responsive only to ghrelin (n = 9) and only to amylin (n = 7) but no cells that responded to both peptides. These data support a role for the SFO as a center at which ghrelin and amylin may influence separate subpopulations of neurons to influence the hypothalamic regulation of feeding.
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Miller DW, Harrison JL, Brown YA, Doyle U, Lindsay A, Adam CL, Lea RG. Immunohistochemical evidence for an endocrine/paracrine role for ghrelin in the reproductive tissues of sheep. Reprod Biol Endocrinol 2005; 3:60. [PMID: 16259638 PMCID: PMC1291400 DOI: 10.1186/1477-7827-3-60] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/31/2005] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The gut hormone, ghrelin, is involved in the neuroendocrine and metabolic responses to hunger. In monogastric species, circulating ghrelin levels show clear meal-related and body weight-related changes. The pattern of secretion and its role in ruminant species is less clear. Ghrelin acts via growth hormone secretagogue receptors (GHSR-1a) to alter food intake, fat utilization, and cellular proliferation. There is also evidence that ghrelin is involved in reproductive function. In the present study we used immunohistochemistry to investigate the presence of ghrelin and GHSR-1a in sheep reproductive tissues. In addition, we examined whether ghrelin and GHSR-1a protein expression is developmentally regulated in the adult and fetal ovine testis, and whether there is an association with markers of cellular proliferation, i.e. stem cell factor (SCF) and proliferating cell nuclear antigen (PCNA). METHODS Antibodies raised against ghrelin and its functional receptor, GHSR-type 1a, were used in standard immunohistochemical protocols on various reproductive tissues collected from adult and fetal sheep. GHSR-1a mRNA presence was also confirmed by in situ hybridisation. SCF and PCNA immunoexpression was investigated in fetal testicular samples. Adult and fetal testicular immunostaining for ghrelin, GHSR-1a, SCF and PCNA was analysed using computer-aided image analysis. Image analysis data were subjected to one-way ANOVA, with differences in immunostaining between time-points determined by Fisher's least significant difference. RESULTS In adult sheep tissue, ghrelin and GHSR-1a immunostaining was detected in the stomach (abomasum), anterior pituitary gland, testis, ovary, and hypothalamic and hindbrain regions of the brain. In the adult testis, there was a significant effect of season (photoperiod) on the level of immunostaining for ghrelin (p < 0.01) and GHSR-1a (p < 0.05). In the fetal sheep testis, there was a significant effect of gestational age on the level of immunostaining for ghrelin (p < 0.001), GHSR-1a (p < 0.05), SCF (p < 0.05) and PCNA (p < 0.01). CONCLUSION Evidence is presented for the presence of ghrelin and its receptor in various reproductive tissues of the adult and fetal sheep. In addition, the data indicate that testicular expression of ghrelin and its receptor is physiologically regulated in the adult and developmentally regulated in the fetus. Therefore, the ghrelin ligand/receptor system may have a role (endocrine and/or paracrine) in the development (cellular proliferation) and function of the reproductive axis of the sheep.
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Affiliation(s)
- David W Miller
- School of Veterinary and Biomedical Sciences, Murdoch University, South Street, Murdoch, WA, Australia
- Sustainable Livestock Systems Group, Scottish Agricultural College, Bucksburn, Aberdeen, UK
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Joanne L Harrison
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
- Early Life Nutrition Group, Rowett Research Institute, Greenburn Rd, Bucksburn, Aberdeen, UK
| | - Yvonne A Brown
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Una Doyle
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Alanna Lindsay
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Clare L Adam
- Early Life Nutrition Group, Rowett Research Institute, Greenburn Rd, Bucksburn, Aberdeen, UK
| | - Richard G Lea
- Early Life Nutrition Group, Rowett Research Institute, Greenburn Rd, Bucksburn, Aberdeen, UK
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Abstract
In mammals, proper gonadal function critically relies on a complex regulatory network of systemic (endocrine) and locally-produced (paracrine and autocrine) signals. Among others, a number of factors primarily involved in the control of energy balance and metabolism have been proven as putative modulators of the gonadal axis, thus providing the basis for the well-known link between energy homeostasis and fertility. Ghrelin, the endogenous ligand of the GH secretagogue receptor (GHS-R), has been recently demonstrated as a pleiotropic regulator involved in a large array of endocrine and non-endocrine functions, including food intake and energy balance. However, the potential reproductive role of this newly discovered molecule has remained largely neglected. Yet, we review herein several lines of evidence which strongly suggest the involvement of ghrelin in the control of some aspects of gonadal function. Thus, expression of ghrelin has been demonstrated in mature Leydig cells of rat and human testis, as well as in steroidogenically active luteal and interstitial hilus cells of the ovary. In addition, expression of the functional ghrelin receptor, the GHS-R type 1a, has been shown in Sertoli and Leydig cells of the testis, and in follicular, luteal, surface epithelial and interstitial hilus cells of the ovary. In terms of function, ghrelin has been proven to dose-dependently inhibit testicular testosterone secretion in vitro, and to modulate Leydig cell proliferation in vivo, as well as the expression of relevant testicular genes, such as that encoding stem cell factor. Moreover, extragonadal actions of ghrelin upon the reproductive axis have been also reported, as ghrelin was able to suppress LH secretion in vivo and to decrease LH responsiveness to GnRH in vitro. In summary, the data so far available strongly suggest that, through local and/or systemic actions, ghrelin operates as a novel regulator of gonadal function that may contribute to the integrated control of energy balance and reproduction.
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Affiliation(s)
- Manuel Tena-Sempere
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Faculty of Medicine, University of Córdoba, Avda. Menéndez Pidal s/n, 14004 Córdoba, Spain.
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Gambineri A, Pagotto U, De Lasio R, Meriggiola MC, Costantino A, Patton L, Pelusi C, Pelusi G, Pasquali R. Short-term modification of sex hormones is associated with changes in ghrelin circulating levels in healthy normal-weight men. J Endocrinol Invest 2005; 28:241-6. [PMID: 15952409 DOI: 10.1007/bf03345380] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The aim of this study was to evaluate the effect of selective and short-term sex hormone modifications on ghrelin levels in normal-weight eugonadal men undergoing hormonal contraceptive treatments. Seven men received an oral progestin [cyproterone acetate (CPA) or dienogest (DNG)] 10 mg/day for 3 weeks (CPA-DNG group), 7 CPA orally 5 mg/day in association with testosterone enanthate (TE) im 200 mg/week for 8 weeks (CPA-TE group), and 7 placebo (PLAC) for 8 weeks (PLAC group). Anthropometry and blood levels of LH, FSH, testosterone, estradiol, glucose, insulin and total ghrelin were evaluated. At baseline, no parameters differed among the three groups. After treatment, LH and FSH decreased in both CPA-DNG and CPA-TE groups, whereas they did not change in the PLAC group. Testosterone and estradiol decreased in the CPA-DNG group to the hypogonadal range, increased in the CPA-TE group to supraphysiological concentrations and, as expected, remained unchanged in the PLAC group. Total ghrelin levels increased in the CPA-DNG, decreased in the CPA-TE and did not change in the PLAC group. Ns modifications in the other parameters were observed in any group, demonstrating that the short-term changes of circulating sex hormones are able to modify ghrelin levels. These data, therefore, suggest that sex steroids are important regulators of ghrelin in normal-weight healthy men too.
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Affiliation(s)
- A Gambineri
- Endocrinology Unit, Department of Internal Medicine, and Center for Applied Biomedical Research (C.R.B.A.), S. Orsola-Malpighi Hospital, Bologna, Italy
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Fernández-Fernández R, Tena-Sempere M, Navarro VM, Barreiro ML, Castellano JM, Aguilar E, Pinilla L. Effects of ghrelin upon gonadotropin-releasing hormone and gonadotropin secretion in adult female rats: in vivo and in vitro studies. Neuroendocrinology 2005; 82:245-55. [PMID: 16721030 DOI: 10.1159/000092753] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 02/14/2006] [Indexed: 01/10/2023]
Abstract
A reproductive facet of ghrelin, a stomach-derived orexigenic peptide involved in energy homeostasis, has been recently suggested, and predominantly inhibitory effects of ghrelin upon luteinizing hormone (LH) secretion have been demonstrated in rat models. Yet, the modulatory actions of ghrelin on the gonadotropic axis remain scarcely evaluated. We report herein a detailed analysis of the effects of ghrelin upon LH and follicle-stimulating hormone (FSH) secretion in the female rat, using a combination of in vivo and in vitro approaches. Intracerebroventricular administration of ghrelin (3 nmol/rat) evoked a significant inhibition of LH secretion in cyclic female rats throughout the estrous cycle (proestrus afternoon, estrus, metestrus), as well as in ovariectomized females. In good agreement, gonadotropin-releasing hormone (GnRH) secretion by hypothalamic fragments from ovariectomized females was significantly inhibited by ghrelin. In contrast, ghrelin dose-dependently stimulated basal LH and FSH secretion by pituitary tissue in vitro; a phenomenon that was proven dependent on the phase of estrous cycle, as it was neither detected at estrus nor observed after ovariectomy. Conversely, GnRH-stimulated LH secretion in vitro was persistently inhibited by ghrelin regardless of the stage of the cycle, whereas stimulated FSH secretion was only inhibited by ghrelin at estrus. In addition, cyclic fluctuations in mRNA levels of growth hormone secretagogue receptor (GHS-R)1a, i.e. the functional ghrelin receptor, were observed in the pituitary, with low values at estrus and metestrus. GHS-R1a mRNA levels, however, remained unchanged after ovariectomy. In summary, our data illustrate a complex mode of action of ghrelin upon the gonadotropic axis, with predominant inhibitory effects at central (hypothalamic) levels and upon GnRH-induced gonadotropin secretion, but direct stimulatory actions on basal LH and FSH secretion. Overall, our results further document the reproductive role of ghrelin, which might be relevant for the integrated control of energy balance and reproduction.
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Jeffery PL, Duncan RP, Yeh AH, Jaskolski RA, Hammond DS, Herington AC, Chopin LK. Expression of the ghrelin axis in the mouse: an exon 4-deleted mouse proghrelin variant encodes a novel C terminal peptide. Endocrinology 2005; 146:432-40. [PMID: 15471962 DOI: 10.1210/en.2003-1466] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin, an n-octanoylated 28-amino-acid peptide capable of inducing GH secretion and food intake in humans and rats, is the endogenous ligand for the GH secretagogue receptor (GHS-R). Here we describe the expression and tissue distribution of the ghrelin/GHS-R axis in the mouse. We also report for the first time the identification of a novel mouse ghrelin mRNA variant in which there is a complete deletion of exon 4. Translation of this variant mRNA yields a protein containing ghrelin and an alternative C-terminal domain with a unique C-terminal peptide sequence. RT-PCR with primers specific for mouse ghrelin was used to demonstrate the mRNA expression of the full preproghrelin transcript and the exon 4-deleted variant in multiple mouse tissues. Real-time PCR was also employed to quantitate mRNA expression of ghrelin, the novel isoform and a previously reported ghrelin gene variant, ghrelin gene-derived transcript. We also demonstrated the tissue expression of the functional GHS-R in the mouse. Immunohistochemistry, employing antibodies raised against the mature human n-octanoylated ghrelin peptide and the putative C-terminal peptide encoded by the exon 4-deleted proghrelin variant, was used to demonstrate protein expression of ghrelin and the variant in multiple mouse tissues including stomach, kidney, and reproductive tissues. The coexpression of ghrelin and its receptor in a wide range of murine tissues suggests varied autocrine/paracrine roles for these peptides. Exon 4-deleted proghrelin, a novel mouse proghrelin isoform with a unique C-terminal peptide sequence, is also widely expressed in the mouse and thus may possess biological activity in these tissues.
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Affiliation(s)
- P L Jeffery
- Ghrelin Research Group, School of Life Sciences, Queensland University of Technology, Brisbane 4001, Australia.
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Barreiro ML, Gaytan F, Castellano JM, Suominen JS, Roa J, Gaytan M, Aguilar E, Dieguez C, Toppari J, Tena-Sempere M. Ghrelin inhibits the proliferative activity of immature Leydig cells in vivo and regulates stem cell factor messenger ribonucleic acid expression in rat testis. Endocrinology 2004; 145:4825-34. [PMID: 15284210 DOI: 10.1210/en.2004-0732] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ghrelin has emerged as putative regulator of an array of endocrine and nonendocrine functions, including cell proliferation. Recently, we provided evidence for the expression of ghrelin in mature, but not in undifferentiated, Leydig cells of rat and human testis. Yet testicular actions of ghrelin, other than modulation of testosterone secretion, remain unexplored. In the present study we evaluated the effects of ghrelin on proliferation of Leydig cell precursors during puberty and after selective elimination of mature Leydig cells by treatment with ethylene dimethane sulfonate. In these settings, intratesticular injection of ghrelin significantly decreased the proliferative activity of differentiating immature Leydig cells, estimated by 5-bromodeoxyuridine labeling. This response was selective and associated, in ethylene dimethane sulfonate-treated animals, with a decrease in the mRNA levels of stem cell factor (SCF), i.e. a key signal in spermatogenesis and a putative regulator of Leydig cell development. Thus, the effects of ghrelin on SCF gene expression were evaluated. In adult rats, ghrelin induced a significant decrease in SCF mRNA levels in vivo. Such an inhibitory action was also detected in vitro using cultures of staged seminiferous tubules. The inhibitory effect of ghrelin in vivo was dependent on proper FSH input, because it was detected in hypophysectomized rats only after FSH replacement. Overall, it is proposed that acquisition of ghrelin expression by Leydig cell precursors during differentiation may operate as a self-regulatory signal for the inhibition of the proliferative activity of this cell type through direct or indirect (i.e. SCF-mediated) mechanisms. In addition, we present novel evidence for the ability of ghrelin to modulate the expression of the SCF gene, which may have implications for the mode of action of this molecule in the testis as well as in other physiological systems.
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Affiliation(s)
- M L Barreiro
- Physiology Section, Department of Cell Biology, Physiology, and Immunology, Faculty of Medicine, University of Cordoba, Avda. Menéndez Pidal s/n, 14004 Cordoba, Spain
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