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Athar F, Karmani M, Templeman N. Metabolic hormones are integral regulators of female reproductive health and function. Biosci Rep 2024; 44:BSR20231916. [PMID: 38131197 PMCID: PMC10830447 DOI: 10.1042/bsr20231916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 11/29/2023] [Accepted: 12/21/2023] [Indexed: 12/23/2023] Open
Abstract
The female reproductive system is strongly influenced by nutrition and energy balance. It is well known that food restriction or energy depletion can induce suppression of reproductive processes, while overnutrition is associated with reproductive dysfunction. However, the intricate mechanisms through which nutritional inputs and metabolic health are integrated into the coordination of reproduction are still being defined. In this review, we describe evidence for essential contributions by hormones that are responsive to food intake or fuel stores. Key metabolic hormones-including insulin, the incretins (glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1), growth hormone, ghrelin, leptin, and adiponectin-signal throughout the hypothalamic-pituitary-gonadal axis to support or suppress reproduction. We synthesize current knowledge on how these multifaceted hormones interact with the brain, pituitary, and ovaries to regulate functioning of the female reproductive system, incorporating in vitro and in vivo data from animal models and humans. Metabolic hormones are involved in orchestrating reproductive processes in healthy states, but some also play a significant role in the pathophysiology or treatment strategies of female reproductive disorders. Further understanding of the complex interrelationships between metabolic health and female reproductive function has important implications for improving women's health overall.
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Affiliation(s)
- Faria Athar
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Muskan Karmani
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Nicole M. Templeman
- Department of Biology, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
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Szymanska K, Rytelewska E, Zaobidna E, Kiezun M, Gudelska M, Kopij G, Dobrzyn K, Mlyczynska E, Kurowska P, Kaminska B, Nynca A, Smolinska N, Rak A, Kaminski T. The Effect of Visfatin on the Functioning of the Porcine Pituitary Gland: An In Vitro Study. Cells 2023; 12:2835. [PMID: 38132154 PMCID: PMC10742260 DOI: 10.3390/cells12242835] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023] Open
Abstract
Visfatin (VIS), also known as nicotinamide phosphoribosyltransferase (NAMPT), is the rate-limiting enzyme in the biosynthesis of nicotinamide adenine dinucleotide (NAD+). Recently, VIS has been also recognized as an adipokine. Our previous study revealed that VIS is produced in the anterior and posterior lobes of the porcine pituitary. Moreover, the expression and secretion of VIS are dependent on the phase of the estrous cycle and/or the stage of early pregnancy. Based on this, we hypothesized that VIS may regulate porcine pituitary function. This study was conducted on anterior pituitary (AP) glands harvested from pigs during specific phases of the estrous cycle. We have shown the modulatory effect of VIS in vitro on LH and FSH secretion by porcine AP cells (determined by ELISA). VIS was also found to stimulate cell proliferation (determined by Alamar Blue) without affecting apoptosis in these cells (determined using flow cytometry technique). Moreover, it was indicated that VIS may act in porcine AP cells through the INSR, AKT/PI3K, MAPK/ERK1/2, and AMPK signaling pathways (determined by ELISA or Western Blot). This observation was further supported by the finding that simultaneous treatment of cells with VIS and inhibitors of these pathways abolished the observed VIS impact on LH and FSH secretion (determined by ELISA). In addition, our research indicated that VIS affected the mentioned processes in a manner that was dependent on the dose of VIS and/or the phase of the estrous cycle. Thus, these findings suggest that VIS may regulate the functioning of the porcine pituitary gland during the estrous cycle.
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Affiliation(s)
- Karolina Szymanska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Edyta Rytelewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Ewa Zaobidna
- Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Marta Kiezun
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Marlena Gudelska
- Department of Human Histology and Embryology, School of Medicine, Collegium Medicum, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland;
| | - Grzegorz Kopij
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Kamil Dobrzyn
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland;
| | - Ewa Mlyczynska
- 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.); (A.R.)
- Doctoral School of Exact and Natural Sciences, Jagiellonian University in Krakow, 30-348 Krakow, Poland
| | - 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.); (A.R.)
| | - Barbara Kaminska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Anna Nynca
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - Nina Smolinska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
| | - 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.); (A.R.)
| | - Tadeusz Kaminski
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, 10-719 Olsztyn, Poland; (K.S.); (E.R.); (M.K.); (G.K.); (B.K.); (A.N.); (N.S.)
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Szymanska K, Zaobidna E, Rytelewska E, Mlyczynska E, Kurowska P, Dobrzyn K, Kiezun M, Kaminska B, Smolinska N, Rak A, Kaminski T. Visfatin in the porcine pituitary gland: expression and regulation of secretion during the oestrous cycle and early pregnancy. Sci Rep 2023; 13:18253. [PMID: 37880346 PMCID: PMC10600231 DOI: 10.1038/s41598-023-45255-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Visfatin is a multifunctional protein which, besides the control of energy homeostasis, seems to be also involved in the regulation of female fertility through the influence on the endocrine hypothalamus-pituitary-gonadal axis, including the pituitary. The aim of this study was to investigate the expression of visfatin mRNA and protein in the anterior (AP) and posterior pituitary lobes of the pig during the oestrous cycle and early pregnancy. In AP, we also examined colocalisation of visfatin with pituitary tropic hormones. Moreover, we aimed to evaluate the in vitro effects of GnRH, FSH, LH, and insulin on visfatin protein concentration and secretion in AP cells during the cycle. The study showed that visfatin is present in all types of porcine pituitary endocrine cells and its expression is reliant on stage of the cycle or pregnancy. GnRH, FSH, LH and insulin stimulated visfatin secretion by AP cells on days 17 to 19 of the cycle, while on days 2 to 3 visfatin release was enhanced only by LH. Summarising, visfatin is locally produced in the pituitary in a way dependent on hormonal milieu typical for reproductive status of pigs. Further research is required to clarify the role of visfatin in the pituitary gland.
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Affiliation(s)
- Karolina Szymanska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Ewa Zaobidna
- Department of Biochemistry, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Edyta Rytelewska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Ewa Mlyczynska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University in Krakow, Lojasiewicza 11, 30-348, Krakow, Poland
| | - Patrycja Kurowska
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
| | - Kamil Dobrzyn
- Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, 10-719, Olsztyn, Poland
| | - Marta Kiezun
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Barbara Kaminska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Nina Smolinska
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland
| | - Agnieszka Rak
- Laboratory of Physiology and Toxicology of Reproduction, Institute of Zoology and Biomedical Research, Jagiellonian University in Krakow, Gronostajowa 9, 30-387, Krakow, Poland
| | - Tadeusz Kaminski
- Department of Animal Anatomy and Physiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719, Olsztyn, Poland.
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Emami MR, Safabakhsh M, Khorshidi M, Moradi Moghaddam O, Mohammed SH, Zarezadeh M, Alizadeh S. Effect of bariatric surgery on endogenous sex hormones and sex hormone-binding globulin levels: a systematic review and meta-analysis. Surg Obes Relat Dis 2021; 17:1621-1636. [PMID: 34187743 DOI: 10.1016/j.soard.2021.05.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 04/14/2021] [Accepted: 05/06/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Most studies have shown beneficial effect of bariatric surgery (BS) on serum levels of sex hormones. OBJECTIVE A systematic review and meta-analysis was conducted to examine the magnitude of possible changes in levels of sex hormones following BS. SETTINGS Electronic databases were searched, including PubMed, Scopus, Web of Science, and Embase, for relevant studies. METHODS The heterogeneity of the studies was examined by χ2 tests and the degree of heterogeneity was estimated using I2 statistic. RESULTS The results of pooled analyses revealed that BS caused a significant increase in luteinizing hormone (LH), follicular stimulating hormone (FSH), total testosterone (TT), and sex hormone binding globulin (SHBG) levels and conversely, decreased dehydroepiandrosterone (DHEA) and estradiol (E2) levels in males. For females, BS significantly increased LH, FSH, and SHBG levels and conversely, decreased androstenedione (AE), E2 and TT levels. Additionally, the level of progesterone (P), prolactin (PRL), free testosterone (FT) and dehydroepiandrosterone sulfate (DHEA-S) showed no significant changes in patients who had undergone BS. CONCLUSION BS changed most sex hormones levels including LH, FSH, TT, SHBG, AE, DHEA, and E2. It seems that BS is able to exert substantial impacts on sex hormones levels and as well as sexual function, however, larger, and more precise trials are required to specifically focus on these claims.
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Affiliation(s)
- Mohammad Reza Emami
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Safabakhsh
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Khorshidi
- Pediatric Gastroenterology, Hepatology and Nutrition Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Pediatric Gastroenterology, Hepatology and Nutrition Research Center, Research Institute for Children's Health, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Omid Moradi Moghaddam
- Trauma and Injury Research Center, Critical Care Medicine Department, Iran University of Medical Sciences, Tehran, Iran
| | - Shimels Hussien Mohammed
- Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences-International Campus, Tehran, Iran
| | - Meysam Zarezadeh
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran; Nutrition Research Center, Department of Clinical Nutrition, School of Nutrition and Food Science, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Shahab Alizadeh
- Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran
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5
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Evans MC, Hill JW, Anderson GM. Role of insulin in the neuroendocrine control of reproduction. J Neuroendocrinol 2021; 33:e12930. [PMID: 33523515 DOI: 10.1111/jne.12930] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/18/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022]
Abstract
Infertility associated with insulin resistance is characterised by abnormal hormone secretion by the hypothalamus, pituitary gland and gonads. These endocrine tissues can maintain insulin sensitivity even when tissues such as the muscle and liver become insulin-resistant, resulting in excessive insulin stimulation as hyperinsulinaemia develops. Experiments conducted to determine the role of neuronal insulin signalling in fertility were unable to recapitulate early findings of hypogonadotrophic hypogonadism in mice lacking insulin receptors throughout the brain. Rather, it was eventually shown that astrocytes critically mediate the effects of insulin on puberty timing and adult reproductive function. However, specific roles for neurones and gonadotrophs have been revealed under conditions of hyperinsulinaemia and by ablation of insulin and leptin receptors. The collective picture is one of multiple insulin-responsive inputs to gonadotrophin releasing hormone neurones, with astrocytes being the most important player.
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Affiliation(s)
- Maggie C Evans
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
| | - Jennifer W Hill
- Department of Physiology and Pharmacology, University of Toledo, Toledo, OH, USA
| | - Greg M Anderson
- Centre for Neuroendocrinology and Department of Anatomy, University of Otago, Dunedin, New Zealand
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Lainez NM, Coss D. Obesity, Neuroinflammation, and Reproductive Function. Endocrinology 2019; 160:2719-2736. [PMID: 31513269 PMCID: PMC6806266 DOI: 10.1210/en.2019-00487] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/04/2019] [Indexed: 12/13/2022]
Abstract
The increasing occurrence of obesity has become a significant public health concern. Individuals with obesity have higher prevalence of heart disease, stroke, osteoarthritis, diabetes, and reproductive disorders. Reproductive problems include menstrual irregularities, pregnancy complications, and infertility due to anovulation, in women, and lower testosterone and diminished sperm count, in men. In particular, women with obesity have reduced levels of both gonadotropin hormones, and, in obese men, lower testosterone is accompanied by diminished LH. Taken together, these findings indicate central dysregulation of the hypothalamic-pituitary-gonadal axis, specifically at the level of the GnRH neuron function, which is the final brain output for the regulation of reproduction. Obesity is a state of hyperinsulinemia, hyperlipidemia, hyperleptinemia, and chronic inflammation. Herein, we review recent advances in our understanding of how these metabolic and immune changes affect hypothalamic function and regulation of GnRH neurons. In the latter part, we focus on neuroinflammation as a major consequence of obesity and discuss findings that reveal that GnRH neurons are uniquely positioned to respond to inflammatory changes.
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Affiliation(s)
- Nancy M Lainez
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
| | - Djurdjica Coss
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California
- Correspondence: Djurdjica Coss, PhD, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, 303 SOM Research Building, 900 University Avenue, Riverside, California 92521. E-mail:
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Impact of Bariatric Surgery on Male Sex Hormones and Sperm Quality: a Systematic Review and Meta-Analysis. Obes Surg 2018; 29:334-346. [DOI: 10.1007/s11695-018-3557-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Maillard V, Elis S, Desmarchais A, Hivelin C, Lardic L, Lomet D, Uzbekova S, Monget P, Dupont J. Visfatin and resistin in gonadotroph cells: expression, regulation of LH secretion and signalling pathways. Reprod Fertil Dev 2018; 29:2479-2495. [PMID: 28672116 DOI: 10.1071/rd16301] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 05/21/2017] [Indexed: 12/15/2022] Open
Abstract
Visfatin and resistin appear to interfere with reproduction in the gonads, but their potential action at the hypothalamic-pituitary level is not yet known. The aim of the present study was to investigate the mRNA and protein expression of these adipokines in murine gonadotroph cells and to analyse the effects of different concentrations of recombinant mouse visfatin and resistin (0.01, 0.1, 1 and 10ngmL-1) on LH secretion and signalling pathways in LβT2 cells and/or in primary female mouse pituitary cells. Both visfatin and resistin mRNA and protein were found in vivo in gonadotroph cells. In contrast with resistin, the primary tissue source of visfatin in the mouse was the skeletal muscle, and not adipose tissue. Visfatin and resistin both decreased LH secretion from LβT2 cells after 24h exposure of cells (P<0.03). These results were confirmed for resistin in primary cell culture (P<0.05). Both visfatin (1ngmL-1) and resistin (1ngmL-1) increased AMP-activated protein kinase α phosphorylation in LβT2 cells after 5 or 10min treatment, up to 60min (P<0.04). Extracellular signal-regulated kinase 1/2 phosphorylation was transiently increased only after 5min resistin (1ngmL-1) treatment (P<0.01). In conclusion, visfatin and resistin are expressed in gonadotroph cells and they may affect mouse female fertility by regulating LH secretion at the level of the pituitary.
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Affiliation(s)
- Virginie Maillard
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Sébastien Elis
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Alice Desmarchais
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Céline Hivelin
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Lionel Lardic
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Didier Lomet
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Svetlana Uzbekova
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Philippe Monget
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
| | - Joëlle Dupont
- UMR85 PRC, INRA, CNRS, IFCE, Université de Tours, 37380 Nouzilly, France
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Pandey K, Mizukami Y, Watanabe K, Sakaguti S, Kadokawa H. Deep sequencing of the transcriptome in the anterior pituitary of heifers before and after ovulation. J Vet Med Sci 2017; 79:1003-1012. [PMID: 28442638 PMCID: PMC5487774 DOI: 10.1292/jvms.16-0531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We aimed to determine gene expression patterns in the anterior pituitary (AP) of heifers
before and after ovulation via deep sequencing of the transcriptome (RNA-seq) to identify
new genes and clarify important pathways. Heifers were slaughtered on the estrus day
(pre-ovulation; n=5) or 3 days after ovulation (post-ovulation; n=5) for AP collection. We
randomly selected 4 pre-ovulation and 4 post-ovulation APs, and the ribosomal RNA-depleted
poly (A)+RNA were prepared to assemble next-generation sequencing libraries. The bovine
APs expressed 12,769 annotated genes at pre- or post-ovulation. The sum of the reads per
kilobase of exon model per million mapped reads (RPKM) values of all transcriptomes were
599,676 ± 38,913 and 668,209 ± 23,690, and 32.2 ± 2.6% and 44.0 ± 4.4% of these
corresponded to the AP hormones in the APs of pre- and post-ovulation heifers,
respectively. The bovine AP showed differential expression of 396 genes
(P<0.05) in the pre- and post-ovulation APs. The 396 genes included
two G-protein-coupled receptor (GPCR) genes (GPR61 and
GPR153) and those encoding 13 binding proteins. The AP also expressed
259 receptor and other 364 binding proteins. Moreover, ingenuity pathway analysis for the
396 genes revealed (P=2.4 × 10−3) a canonical pathway linking
GPCR to cytoskeleton reorganization, actin polymerization, microtubule growth, and gene
expression. Thus, the present study clarified the novel genes found to be differentially
expressed before and after ovulation and clarified an important pathway in the AP.
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Affiliation(s)
- Kiran Pandey
- Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida 1677-1, Yamaguchi-shi, Yamaguchi 753-8515, Japan
| | - Yoichi Mizukami
- Center for Gene Research, Yamaguchi University, Minami Kogushi 1-1-1, Ube-shi, Yamaguchi 755-8505, Japan
| | - Kenji Watanabe
- Center for Gene Research, Yamaguchi University, Minami Kogushi 1-1-1, Ube-shi, Yamaguchi 755-8505, Japan
| | - Syuiti Sakaguti
- Institute of Radioisotope Research and Education, Yamaguchi University, Minami Kogushi 1-1-1, Ube-shi, Yamaguchi 755-8505, Japan
| | - Hiroya Kadokawa
- Joint Faculty of Veterinary Medicine, Yamaguchi University, Yoshida 1677-1, Yamaguchi-shi, Yamaguchi 753-8515, Japan
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10
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Cardoso RC, Burns A, Moeller J, Skinner DC, Padmanabhan V. Developmental Programming: Insulin Sensitizer Prevents the GnRH-Stimulated LH Hypersecretion in a Sheep Model of PCOS. Endocrinology 2016; 157:4641-4653. [PMID: 27792406 PMCID: PMC5133353 DOI: 10.1210/en.2016-1613] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Prenatal testosterone (T) treatment recapitulates the reproductive and metabolic phenotypes of polycystic ovary syndrome in female sheep. At the neuroendocrine level, prenatal T treatment results in disrupted steroid feedback on gonadotropin release, increased pituitary sensitivity to GnRH, and subsequent LH hypersecretion. Because prenatal T-treated sheep manifest functional hyperandrogenism and hyperinsulinemia, gonadal steroids and/or insulin may play a role in programming and/or maintaining these neuroendocrine defects. Here, we investigated the effects of prenatal and postnatal treatments with an androgen antagonist (flutamide [F]) or an insulin sensitizer (rosiglitazone [R]) on GnRH-stimulated LH secretion in prenatal T-treated sheep. As expected, prenatal T treatment increased the pituitary responsiveness to GnRH leading to LH hypersecretion. Neither prenatal interventions nor postnatal F treatment normalized the GnRH-stimulated LH secretion. Conversely, postnatal R treatment completely normalized the GnRH-stimulated LH secretion. At the tissue level, gestational T increased pituitary LHβ, androgen receptor, and insulin receptor-β, whereas it reduced estrogen receptor (ER)α protein levels. Although postnatal F normalized pituitary androgen receptor and insulin receptor-β, it failed to prevent an increase in LHβ expression. Contrarily, postnatal R treatment restored ERα and partially normalized LHβ pituitary levels. Immunohistochemical findings confirmed changes in pituitary ERα expression to be specific to gonadotropes. In conclusion, these findings indicate that increased pituitary responsiveness to GnRH in prenatal T-treated sheep is likely a function of reduced peripheral insulin sensitivity. Moreover, results suggest that restoration of ERα levels in the pituitary may be one mechanism by which R prevents GnRH-stimulated LH hypersecretion in this sheep model of polycystic ovary syndrome-like phenotype.
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Affiliation(s)
- Rodolfo C Cardoso
- Department of Pediatrics (R.C.C., A.B., J.M., V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Zoology and Physiology (D.C.S.), University of Wyoming, Laramie, Wyoming 82071
| | - Ashleigh Burns
- Department of Pediatrics (R.C.C., A.B., J.M., V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Zoology and Physiology (D.C.S.), University of Wyoming, Laramie, Wyoming 82071
| | - Jacob Moeller
- Department of Pediatrics (R.C.C., A.B., J.M., V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Zoology and Physiology (D.C.S.), University of Wyoming, Laramie, Wyoming 82071
| | - Donal C Skinner
- Department of Pediatrics (R.C.C., A.B., J.M., V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Zoology and Physiology (D.C.S.), University of Wyoming, Laramie, Wyoming 82071
| | - Vasantha Padmanabhan
- Department of Pediatrics (R.C.C., A.B., J.M., V.P.), University of Michigan, Ann Arbor, Michigan 48109; and Department of Zoology and Physiology (D.C.S.), University of Wyoming, Laramie, Wyoming 82071
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11
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Pereira A, Corvalán C, Uauy R, Klein KO, Mericq V. Ultrasensitive estrogen levels at 7 years of age predict earlier thelarche: evidence from girls of the growth and obesity Chilean cohort. Eur J Endocrinol 2015; 173:835-42. [PMID: 26369578 DOI: 10.1530/eje-15-0327] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 09/08/2015] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Prepubertal estradiol equivalents have been inconsistently linked to age at thelarche; elucidating this relationship becomes relevant given the worldwide decline in the age of puberty onset. Thus, our aim is to assess whether prepubertal girls with higher serum levels of estradiol equivalents at age 7 have a greater risk of presenting early thelarche (ET). DESIGN Nested case-control study within the Growth and Obesity Cohort Study of 1196 low-middle income children (∼50% girls) from Santiago, Chile. Girls were defined as cases (ET; n=61) if breast bud appeared prior to 8 years of age; controls (n=91) had thelarche >8 years. METHODS At 6.7 years, weight, height and waist circumference were measured and a fasting blood sample was obtained for measuring estrogen equivalent (ultrasensitive recombinant cell bioassay), DHEAS, leptin, insulin and IGF1. Beginning at 7 years old, Tanner staging was assessed prospectively twice a year and the appearance of breast bud was assessed by palpation. RESULTS Mean serum estradiol-equivalent at 6.7 years was 3.9±3.6 pg/ml for cases and 3.6±2.3 pg/ml for controls. Girls with ET had a higher risk of presenting elevated estradiol-equivalent (≥5 pg/ml) at 7 years (OR=2.05, 95% CI: 0.96-4.36) than controls that was borderline significant. However, after adjusting by BMI, insulin and IGF1 at age 7, the association between estradiol-equivalent and ET was significant (OR=2.29 (95% CI: 1.05-5.01)). CONCLUSIONS Chilean girls from low to middle socioeconomic status with ET exhibited double the risk of having high levels of estradiol-equivalent at 7 years than girls with a later age of thelarche. Whole-body adiposity and increased adrenal activity did not explain the observed prepubertal estrogen increase.
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Affiliation(s)
- Ana Pereira
- Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile
| | - Camila Corvalán
- Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile
| | - Ricardo Uauy
- Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile
| | - Karen O Klein
- Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile
| | - Verónica Mericq
- Institute of Nutrition and Food TechnologyUniversity of Chile, Avenida El Líbano 5524, Macul, Santiago, ChileDepartment of NeonatologyFaculty of Medicine, Catholic University of Chile, Santiago, ChileDepartment of PediatricsUniversity of California, San Diego, California, USAInstitute of Maternal and Child ResearchFaculty of Medicine, University of Chile, Santiago, Chile
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12
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Skarra DV, Thackray VG. FOXO1 is regulated by insulin and IGF1 in pituitary gonadotropes. Mol Cell Endocrinol 2015; 405:14-24. [PMID: 25676570 PMCID: PMC4363278 DOI: 10.1016/j.mce.2015.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 01/23/2015] [Accepted: 02/04/2015] [Indexed: 10/24/2022]
Abstract
The FOXO1 transcription factor is important for multiple aspects of reproductive function. We previously reported that FOXO1 functions as a repressor of gonadotropin hormone synthesis, but how FOXO1 is regulated in pituitary gonadotropes is unknown. The growth factors, insulin and insulin-like growth factor I (IGF1), function as key regulators of cell proliferation, metabolism and apoptosis in multiple cell types through the PI3K/AKT signaling pathway. In this study, we found that insulin and IGF1 signaling in gonadotropes induced FOXO1 phosphorylation through the PI3K/AKT pathway in immortalized and primary cells, resulting in FOXO1 relocation from the nucleus to the cytoplasm. Furthermore, insulin administration in vivo induced phosphorylation of FOXO1 and AKT in the pituitary. Thus, insulin and IGF1 act as negative regulators of FOXO1 activity and may serve to fine-tune gonadotropin expression.
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Affiliation(s)
- Danalea V Skarra
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Varykina G Thackray
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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13
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Cardoso RC, Puttabyatappa M, Padmanabhan V. Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions. Neuroendocrinology 2015; 102:226-37. [PMID: 25832114 PMCID: PMC4591099 DOI: 10.1159/000381830] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 03/21/2015] [Indexed: 12/12/2022]
Abstract
The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids due to disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone, luteinizing hormone excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal testosterone treatment also leads to fetal growth retardation, insulin resistance, and hypertension. Mounting evidence suggests that developmental exposure to an improper steroidal/metabolic environment may mediate the programming of adult disorders in prenatal testosterone-treated females, and these defects are maintained or amplified by the postnatal sex steroid and metabolic milieu. This review addresses the steroidal and metabolic contributions to the development and maintenance of the PCOS phenotype in the prenatal testosterone-treated sheep model, including the effects of prenatal and postnatal treatment with an androgen antagonist or insulin sensitizer as potential strategies to prevent/ameliorate these dysfunctions. Insights obtained from these intervention strategies on the mechanisms underlying these defects are likely to have translational relevance to human PCOS.
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Affiliation(s)
- Rodolfo C Cardoso
- Department of Pediatrics, University of Michigan, Ann Arbor, Mich., USA
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14
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Park CH, Skarra DV, Rivera AJ, Arriola DJ, Thackray VG. Constitutively active FOXO1 diminishes activin induction of Fshb transcription in immortalized gonadotropes. PLoS One 2014; 9:e113839. [PMID: 25423188 PMCID: PMC4244159 DOI: 10.1371/journal.pone.0113839] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/31/2014] [Indexed: 11/29/2022] Open
Abstract
In the present study, we investigate whether the FOXO1 transcription factor modulates activin signaling in pituitary gonadotropes. Our studies show that overexpression of constitutively active FOXO1 decreases activin induction of murine Fshb gene expression in immortalized LβT2 cells. We demonstrate that FOXO1 suppression of activin induction maps to the −304/−95 region of the Fshb promoter containing multiple activin response elements and that the suppression requires the FOXO1 DNA-binding domain (DBD). FOXO1 binds weakly to the −125/−91 region of the Fshb promoter in a gel-shift assay. Since this region of the promoter contains a composite SMAD/FOXL2 binding element necessary for activin induction of Fshb transcription, it is possible that FOXO1 DNA binding interferes with SMAD and/or FOXL2 function. In addition, our studies demonstrate that FOXO1 directly interacts with SMAD3/4 but not SMAD2 in a FOXO1 DBD-dependent manner. Moreover, we show that SMAD3/4 induction of Fshb-luc and activin induction of a multimerized SMAD-binding element-luc are suppressed by FOXO1 in a DBD-dependent manner. These results suggest that FOXO1 binding to the proximal Fshb promoter as well as FOXO1 interaction with SMAD3/4 proteins may result in decreased activin induction of Fshb in gonadotropes.
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Affiliation(s)
- Chung Hyun Park
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Danalea V. Skarra
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Alissa J. Rivera
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - David J. Arriola
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA, United States of America
| | - Varykina G. Thackray
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA, United States of America
- * E-mail:
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15
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Wolfe A, Divall S, Wu S. The regulation of reproductive neuroendocrine function by insulin and insulin-like growth factor-1 (IGF-1). Front Neuroendocrinol 2014; 35:558-72. [PMID: 24929098 PMCID: PMC4175134 DOI: 10.1016/j.yfrne.2014.05.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 04/01/2014] [Accepted: 05/27/2014] [Indexed: 12/27/2022]
Abstract
The mammalian reproductive hormone axis regulates gonadal steroid hormone levels and gonadal function essential for reproduction. The neuroendocrine control of the axis integrates signals from a wide array of inputs. The regulatory pathways important for mediating these inputs have been the subject of numerous studies. One class of proteins that have been shown to mediate metabolic and growth signals to the CNS includes Insulin and IGF-1. These proteins are structurally related and can exert endocrine and growth factor like action via related receptor tyrosine kinases. The role that insulin and IGF-1 play in controlling the hypothalamus and pituitary and their role in regulating puberty and nutritional control of reproduction has been studied extensively. This review summarizes the in vitro and in vivo models that have been used to study these neuroendocrine structures and the influence of these growth factors on neuroendocrine control of reproduction.
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Affiliation(s)
- Andrew Wolfe
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States.
| | - Sara Divall
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States
| | - Sheng Wu
- Johns Hopkins University School of Medicine, Department of Pediatrics, Division of Endocrinology, Baltimore, MD 21287, United States
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16
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Abstract
The transcription factor gene Egr1 is necessary for female fertility; EGR1 protein is an established molecular regulator of adult female gonadotroph function where it mediates GNRH-stimulated transcription of the Lhb gene. Recent studies have also implicated pituitary EGR1 in the mediation of other physiological signals indicating an integrative function. However, the role of EGR1 in males is less well defined and this uncertainty is compounded by the absence of cellular expression data in the male pituitary gland. The aim of this study, therefore, was to define the distribution of Egr1 gene expression in the adult male rat pituitary. To further this aim, we have evaluated cellular populations in a transgenic rat model (Egr1-d2EGFP), in which we demonstrate regulated green fluorescent protein (GFP) expression in EGR1+ pituitary cells. Cellular filling by GFP enabled morphological and molecular differentiation of different populations of gonadotrophs; Egr1 transcription and LHB were highly co-localised in a major population of large cells but only minimally co-localised in small GFP+ cells; the latter cells were shown to be largely (80%) composed of minority populations of GH+ somatotrophs (9% of total GH+) and PRL+ lactotrophs (3% of total PRL+). Egr1 transcription was not found in TSH+, ACTH+ or SOX2+ precursor cells and was only minimally co-localised in S-100β+ folliculostellate cells. Our demonstration that the Egr1 gene is actively and selectively transcribed in a major sub-population of male LHB+ cells indicates a largely conserved role in gonadotroph function and has provided a basis for further defining this role.
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Affiliation(s)
- Pui-Sin Man
- School of BiosciencesCardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - Timothy Wells
- School of BiosciencesCardiff University, Museum Avenue, Cardiff CF10 3AX, UK
| | - David A Carter
- School of BiosciencesCardiff University, Museum Avenue, Cardiff CF10 3AX, UK
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17
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Andrade J, Quinn J, Becker RZ, Shupnik MA. AMP-activated protein kinase is a key intermediary in GnRH-stimulated LHβ gene transcription. Mol Endocrinol 2013; 27:828-39. [PMID: 23518923 DOI: 10.1210/me.2012-1323] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GnRH regulation of pituitary gonadotropin gene transcription is critical for fertility, and metabolic dysregulation is associated with reproductive disorders and altered hypothalamic-pituitary responses. Here, we examined signaling pathways in gonadotropes through which GnRH modulates gonadotropin levels, and potential common signaling pathways with insulin. Using LβT2 cells, we show that GnRH rapidly (5 minutes) triggers activating phosphorylation of AMP-activated protein kinase (AMPK) up to 5-fold; this stimulation is enhanced by insulin through increased total AMPKα levels and activity. GnRH also stimulated c-Jun N-terminal kinase (JNK) and ERK activation, whereas insulin alone stimulated Akt. Inhibition of AMPK activity by compound C, or diminishing AMPK levels by small interfering RNA against AMPKα, prevented GnRH-stimulated transcription of the endogenous LHβ gene and transfected LHβ promoter. Egr-1 (early growth response-1), a transcription factor required for LHβ expression, is synthesized in response to GnRH, and compound C prevents this induction. However, overexpression of Egr-1 in the presence of compound C did not restore GnRH stimulation of LHβ, suggesting that AMPK stimulation of transcription also occurs through additional mechanisms or signaling pathways. One such pathway may be JNK activation, because GnRH stimulation of JNK activity and LHβ transcription occurs more slowly than stimulation of AMPK activity, and AMPK inhibition by compound C or small interfering RNA also prevented GnRH-stimulated JNK phosphorylation. Finally, in primary mouse pituitary cells, GnRH also stimulates AMPK, and AMPK inhibition suppresses GnRH-stimulated LHβ transcription. These studies indicate a novel role for AMPK in GnRH-stimulated transcription in pituitary gonadotropes and a potential common mechanism for GnRH and metabolic modulation of fertility.
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Affiliation(s)
- Josefa Andrade
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Virginia, Charlottesville, VA 22903, USA
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18
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Lindaman LL, Yeh DM, Xie C, Breen KM, Coss D. Phosphorylation of ATF2 and interaction with NFY induces c-Jun in the gonadotrope. Mol Cell Endocrinol 2013. [PMID: 23178797 PMCID: PMC3529762 DOI: 10.1016/j.mce.2012.11.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Induction of c-Jun and c-Fos, partners that comprise the AP1 transcription factor, is critical for GnRH regulation of FSHβ gene expression. The signaling pathways that are necessary for regulation of AP1 in the gonadotrope cell are not known. Here, we investigate the mechanism of c-Jun induction by GnRH, the sole regulator of c-Jun in the gonadotrope. We identify that GnRH phosphorylates ATF2 via p38 and JNK, the same pathways responsible for GnRH induction of c-Jun. Upon phosphorylation, ATF2 binds the CRE element within the c-Jun proximal promoter and interacts with NFY. Functional ATF2 is necessary for both GnRH induction of c-Jun and FSHβ. Taken together, these studies elucidate the specificity of c-Jun induction by GnRH in the gonadotrope by demonstrating GnRH activation of the p38 and JNK signaling pathways that lead to phosphorylation of ATF2, providing critical insight into GnRH regulation of its target gene, the gonadotropin subunit FSHβ.
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Affiliation(s)
- Lacey L Lindaman
- Department of Reproductive Medicine, Center for Reproductive Science and Medicine, University of California San Diego, La Jolla, CA 92093-0674, USA.
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19
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Majumdar S, Farris CL, Kabat BE, Jung DO, Ellsworth BS. Forkhead Box O1 is present in quiescent pituitary cells during development and is increased in the absence of p27 Kip1. PLoS One 2012; 7:e52136. [PMID: 23251696 PMCID: PMC3522653 DOI: 10.1371/journal.pone.0052136] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 11/15/2012] [Indexed: 02/07/2023] Open
Abstract
Congenital pituitary hormone deficiencies have been reported in approximately one in 4,000 live births, however studies reporting mutations in some widely studied transcription factors account for only a fraction of congenital hormone deficiencies in humans. Anterior pituitary hormones are required for development and function of several glands including gonads, adrenals, and thyroid. In order to identify additional factors that contribute to human congenital hormone deficiencies, we are investigating the forkhead transcription factor, FOXO1, which has been implicated in development of several organs including ovary, testis, and brain. We find that FOXO1 is present in the nuclei of non-dividing pituitary cells during embryonic development, consistent with a role in limiting proliferation and/or promoting differentiation. FOXO1 is present in a subset of differentiated cells at e18.5 and in adult with highest level of expression in somatotrope cells. We detected FOXO1 in p27(Kip1)-positive cells at e14.5. In the absence of p27(Kip1) the number of pituitary cells containing FOXO1 is significantly increased at e14.5 suggesting that a feedback loop regulates the interplay between FOXO1 and p27(Kip1).
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Affiliation(s)
- Sreeparna Majumdar
- Department of Physiology, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Corrie L. Farris
- Department of Physiology, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Brock E. Kabat
- Department of Physiology, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Deborah O. Jung
- Department of Physiology, Southern Illinois University, Carbondale, Illinois, United States of America
| | - Buffy S. Ellsworth
- Department of Physiology, Southern Illinois University, Carbondale, Illinois, United States of America
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20
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Arriola DJ, Mayo SL, Skarra DV, Benson CA, Thackray VG. FOXO1 transcription factor inhibits luteinizing hormone β gene expression in pituitary gonadotrope cells. J Biol Chem 2012; 287:33424-35. [PMID: 22865884 DOI: 10.1074/jbc.m112.362103] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Synthesis of luteinizing hormone (LH) is tightly controlled by a complex network of hormonal signaling pathways that can be modulated by metabolic cues, such as insulin. One group of candidate genes that may be regulated by insulin signaling in pituitary gonadotrope cells is the FOXO subfamily of forkhead transcription factors. In this study we investigated whether FOXO1 is expressed in gonadotropes and if it can modulate LH β-subunit (Lhb) gene expression. We demonstrated that FOXO1 is expressed in murine gonadotrope cells and that insulin signaling increased FOXO1 phosphorylation and cytoplasmic localization in a PI3K-dependent manner. We also showed that FOXO1 repressed basal transcription and gonadotropin-releasing hormone (GnRH) induction of both the murine and human LHB genes in LβT2 cells, suggesting that FOXO1 regulation of LHB transcription may be conserved between rodents and humans. Although we did not detect FOXO1 binding to the proximal Lhb promoter, the FOXO1 DNA binding domain was necessary for the suppression, suggesting that FOXO1 exerts its effect through protein-protein interactions with transcription factors/cofactors required for Lhb gene expression. FOXO1 repression mapped to the proximal Lhb promoter containing steroidogenic factor 1 (SF1), pituitary homeobox 1 (PTX1), and early growth response protein 1 (EGR1) binding elements. Additionally, FOXO1 blocked induction of the Lhb promoter with overexpressed SF1, PTX1, and EGR1, indicating that FOXO1 repression occurs via these transcription factors but not through regulation of their promoters. In summary, we demonstrate that FOXO1 phosphorylation and cellular localization is regulated by insulin signaling in gonadotropes and that FOXO1 inhibits Lhb transcription. Our study also suggests that FOXO1 may play an important role in controlling LH levels in response to metabolic cues.
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Affiliation(s)
- David J Arriola
- Department of Reproductive Medicine and the Center for Reproductive Science and Medicine, University of California, San Diego, La Jolla, California 92093, USA
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21
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Abi Salloum B, Herkimer C, Lee JS, Veiga-Lopez A, Padmanabhan V. Developmental programming: prenatal and postnatal contribution of androgens and insulin in the reprogramming of estradiol positive feedback disruptions in prenatal testosterone-treated sheep. Endocrinology 2012; 153:2813-22. [PMID: 22454153 PMCID: PMC3359592 DOI: 10.1210/en.2011-2074] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Prenatal testosterone (T) excess compromises the estradiol (E(2)) positive feedback. This study tested the hypothesis that antagonizing androgen action or improving insulin sensitivity prenatally would prevent positive feedback disruptions from developing, whereas postnatal intervention with androgen antagonist or insulin sensitizer would ameliorate the severity of disruptions in prenatal T-treated females. The E(2) positive feedback response was tested at 16 wk of age in the following groups of animals: 1) control, 2) prenatal T, 3) prenatal T plus the androgen antagonist, flutamide, 4) prenatal T plus insulin sensitizer, rosiglitazone, 5) prenatal T and postnatal androgen antagonist, and 6) prenatal T and postnatal insulin sensitizer (n = 7-21 animals/group). Prenatal T treatment involved the administration of T propionate (100 mg, im) twice weekly from d 30 to 90 of gestation. Prenatal interventions involved daily sc administration of androgen antagonist (15 mg/kg) or oral administration of insulin sensitizer (8 mg) for the same duration. Postnatal treatments began at 8 wk of age and involved daily oral administration of androgen antagonist (15 mg/kg) or insulin sensitizer (0.11 mg/kg). None of the prenatal/postnatal interventions increased number of animals responding or prevented the time delay in LH surge response to the E(2) positive feedback challenge. In contrast, the postnatal treatment with androgen antagonist or insulin sensitizer increased total LH released in response to E(2) positive feedback challenge, compared with the T animals. Overall, these interventional studies indicate that timing and magnitude of the LH surge are programmed by different neuroendocrine mechanisms with postnatal androgens and insulin determining the size and prenatal estrogen likely the timing of the LH surge.
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Affiliation(s)
- Bachir Abi Salloum
- Department of Pediatrics and Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan 48109, USA
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22
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CREB binding protein (CBP) activation is required for luteinizing hormone beta expression and normal fertility in mice. Mol Cell Biol 2012; 32:2349-58. [PMID: 22508984 DOI: 10.1128/mcb.00394-12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Normal function of the hypothalamic-pituitary-gonadal axis is dependent on gonadotropin-releasing hormone (GNRH)-stimulated synthesis and secretion of luteinizing hormone (LH) from the pituitary gonadotroph. While the transcriptional coactivator CREB binding protein (CBP) is known to interact with Egr-1, the major mediator of GNRH action on the Lhb gene, the role of CBP in Lhb gene expression has yet to be characterized. We show that in the LβT2 gonadotroph cell line, overexpression of CBP augmented the response to GNRH and that knockdown of CBP eliminated GNRH responsiveness. While GNRH-mediated phosphorylation of CBP at Ser436 increased the interaction with Egr-1 on the Lhb promoter, loss of this phosphorylation site eliminated GNRH-mediated Lhb expression in LβT2 cells. In vivo, loss of CBP phosphorylation at Ser436 rendered female mice subfertile. S436A knock-in mice had disrupted estrous cyclicity and reduced responsiveness to GNRH. Our results show that GNRH-mediated phosphorylation of CBP at Ser436 is required for Egr-1 to activate Lhb expression and is a requirement for normal fertility in female mice. As CBP can be phosphorylated by other factors, such as insulin, our studies suggest that CBP may act as a key regulator of Lhb expression in the gonadotroph by integrating homeostatic information with GNRH signaling.
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Rao SR, Kini S, Tamler R. Sex Hormones and Bariatric Surgery in Men. ACTA ACUST UNITED AC 2011; 8:300-11. [DOI: 10.1016/j.genm.2011.05.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/02/2011] [Accepted: 05/25/2011] [Indexed: 12/31/2022]
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Brothers KJ, Wu S, DiVall SA, Messmer MR, Kahn CR, Miller RS, Radovick S, Wondisford FE, Wolfe A. Rescue of obesity-induced infertility in female mice due to a pituitary-specific knockout of the insulin receptor. Cell Metab 2010; 12:295-305. [PMID: 20816095 PMCID: PMC2935812 DOI: 10.1016/j.cmet.2010.06.010] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 03/17/2010] [Accepted: 06/01/2010] [Indexed: 12/21/2022]
Abstract
Obesity is associated with insulin resistance in metabolic tissues such as adipose, liver, and muscle, but it is unclear whether nonclassical target tissues, such as those of the reproductive axis, are also insulin resistant. To determine if the reproductive axis maintains insulin sensitivity in obesity in vivo, murine models of diet-induced obesity (DIO) with and without intact insulin signaling in pituitary gonadotrophs were created. Diet-induced obese wild-type female mice (WT DIO) were infertile and experienced a robust increase in luteinizing hormone (LH) after gonadotropin-releasing hormone (GnRH) or insulin stimulation. By contrast, both lean and obese mice with a pituitary-specific knockout of the insulin receptor (PitIRKO) exhibited reproductive competency, indicating that insulin signaling in the pituitary is required for the reproductive impairment seen in DIO and that the gonadotroph maintains insulin sensitivity in a setting of peripheral insulin resistance.
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Affiliation(s)
- Kathryn J Brothers
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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Navratil AM, Song H, Hernandez JB, Cherrington BD, Santos SJ, Low JM, Do MHT, Lawson MA. Insulin augments gonadotropin-releasing hormone induction of translation in LbetaT2 cells. Mol Cell Endocrinol 2009; 311:47-54. [PMID: 19632296 PMCID: PMC2739255 DOI: 10.1016/j.mce.2009.07.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 06/23/2009] [Accepted: 07/06/2009] [Indexed: 10/20/2022]
Abstract
The integrated signaling of insulin and gonadotropin-releasing hormone in the pituitary gonadotropes may have a profound bearing on reproductive function, although the cross-receptor signaling mechanisms are unclear. We demonstrate that the insulin receptor is constitutively localized to non-caveolar lipid raft microdomains in the pituitary gonadotrope cell line LbetaT2. The localization to rafts is consistent with similar localization of the GnRH receptor. Insulin receptor phosphorylation occurs in raft domains and activates the downstream signaling targets Insulin Receptor Substrate1 and Akt/Protein Kinase B. Although insulin alone does not strongly activate the extracellular signal-regulated kinase second messenger cascade, co-stimulation potentiates the phosphorylation of the extracellular signal-regulated kinase by gonadotropin-releasing hormone. The co-stimulatory effect of insulin and gonadotropin-releasing hormone is also evident in increased activation of cap-dependent translation. In contrast, co-stimulation attenuates Akt/Protein Kinase B activation. Our results show that both gonadotropin-releasing hormone and insulin are capable of mutually altering their respective regulatory signaling cascades. We suggest that this provides a mechanism to integrate neuropeptide and energy homeostatic signals to modulate reproductive function.
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Affiliation(s)
- Amy M. Navratil
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Hyunjin Song
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Jeniffer B. Hernandez
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Brian D. Cherrington
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Sharon J. Santos
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
| | - Janine M. Low
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093
| | - Minh-Ha T. Do
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093
| | - Mark A. Lawson
- Department of Reproductive Medicine, University of California, San Diego, La Jolla, CA 92093
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Olivares A, Méndez JP, Cárdenas M, Oviedo N, Palomino MA, Santos I, Perera-Marín G, Gutiérrez-Sagal R, Ulloa-Aguirre A. Pituitary-testicular axis function, biological to immunological ratio and charge isoform distribution of pituitary LH in male rats with experimental diabetes. Gen Comp Endocrinol 2009; 161:304-12. [PMID: 19523385 DOI: 10.1016/j.ygcen.2008.12.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 12/02/2008] [Accepted: 12/03/2008] [Indexed: 01/23/2023]
Abstract
Men with insulinopenic diabetes mellitus frequently present hypogonadism and exhibit circulating luteinizing hormone (LH) molecules with increased biological activity. To further study this latter issue, we analyzed the pattern of isoform distribution and the impact of changes in terminal glycosylation of pituitary LH on the bioactivity of this gonadotropin in experimental diabetes. Adult male rats were treated with streptozotocin or vehicle and euthanized on days 30, 60, or 90 posttreatment. All diabetic groups exhibited a significant decrease in serum insulin and testosterone levels as well as in sperm count; serum gonadotropins and 17beta-estradiol decreased only after 90 days of insulinopenia. Both the immunoreactive concentrations and the biological to immunological ratio of intrapituitary LH significantly increased in all experimental groups, as assessed by an in vitro homologous bioassay in HEK-293 cells expressing a recombinant LH receptor. Chromatofocusing of pituitary extracts revealed the presence of multiple LH charge isoforms; the pH distribution profile of LH in diabetic and control rats was indistinguishable on days 30 and 60 posttreatment. By contrast, the abundance of more basic isoforms (pH 9.99-9.0) decreased and that of isoforms with pH values 8.99-8.0 increased in rats with long-standing diabetes compared to controls. It is concluded that experimental diabetes alters the function of the pituitary-testicular axis, resulting in reduced sex steroids levels and hypogonadotropism. Long-standing insulinopenia leads to a paradoxical accumulation of intrapituitary LH molecules enriched in bioactivity with altered terminal glycosylation, which are apparently subserved by distinct mechanisms involving altered hypothalamic and/or gonadal inputs on the gonadotrope.
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Affiliation(s)
- Aleida Olivares
- Research Unit in Developmental Biology, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, 06720 México D.F., Mexico.
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Walsh HE, Shupnik MA. Proteasome regulation of dynamic transcription factor occupancy on the GnRH-stimulated luteinizing hormone beta-subunit promoter. Mol Endocrinol 2008; 23:237-50. [PMID: 19095772 DOI: 10.1210/me.2008-0098] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GnRH is the main modulator of LH secretion and transcription of the LH subunit genes in pituitary gonadotropes. The LHbeta gene is preferentially transcribed during pulsatile GnRH stimuli of one pulse/30 min and is thus carefully controlled by specific signaling pathways and transcription factors. We now show that GnRH-stimulated LHbeta transcription is also influenced by the ubiquitin-proteasome system. GnRH-stimulated activity of an LHbeta reporter gene was prevented by proteasome inhibitors MG-132 and lactacystin. Inhibition was not rescued by overexpression of two key transcription factors for LHbeta, early growth response-1 (Egr-1) and steroidogenic factor-1 (SF-1). Increased endogenous LHbeta transcription after GnRH treatment was also prevented by MG-132, as measured by primary transcript assays. To investigate possible mechanisms of LHbeta transcriptional inhibition by proteasome blockade, we employed chromatin immunoprecipitation to measure LHbeta promoter occupancy by transcription factors. Without GnRH, binding was low and unorganized. With GnRH, Egr-1 and SF-1 associations were stimulated, cyclic, and coincidental, with a period of approximately 30 min. MG-132 disrupted GnRH-induced Egr-1 and SF-1 binding and prevented phosphorylated RNA polymerase II association with the LHbeta promoter. Egr-1, but not SF-1, protein was induced by GnRH and accumulated with MG-132. Egr-1 and SF-1 were ubiquitinated in gonadotropes and ubiquitinated forms of these factors associated with the LHbeta promoter, suggesting their degradation may be key for LHbeta proteasome-dependent transcription. Together, these results demonstrate that degradation via the proteasome is vital to GnRH-stimulated LHbeta expression, and this occurs in part by allowing proper transcription factor associations with the LHbeta promoter.
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Affiliation(s)
- Heidi E Walsh
- University of Virginia, Charlottesville, Virginia 22908, USA
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Lawson MA, Jain S, Sun S, Patel K, Malcolm PJ, Chang RJ. Evidence for insulin suppression of baseline luteinizing hormone in women with polycystic ovarian syndrome and normal women. J Clin Endocrinol Metab 2008; 93:2089-96. [PMID: 18334581 PMCID: PMC2435648 DOI: 10.1210/jc.2007-2656] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT In women with polycystic ovarian syndrome (PCOS), the relationship of insulin to LH secretion and responses to GnRH remains unresolved. A rigorous analytical examination of this relationship has not been performed. OBJECTIVE Our objective was to determine the relationship of basal LH secretion and responses to GnRH, insulin, and other endocrine variables in normal and PCOS women. DESIGN In PCOS and normal women, mean composite 12-h LH secretion was analyzed for correlating factors. LH responses to varying doses of GnRH during a fixed rate of insulin infusion and LH responses to a fixed dose of GnRH during varying doses of insulin infusion were analyzed for contributing factors. PATIENTS AND SETTING Eighteen PCOS and 21 normal women underwent studies of frequent blood sampling and GnRH stimulation before and during insulin infusion at the General Clinical Research Center, University of California, San Diego. MAIN OUTCOME MEASURES Group mean composite 12-h LH levels were assessed with respect to other endocrine variables. In addition, LH responses to GnRH with or without insulin infusion were assessed. RESULTS In normal women, insulin negatively predicted mean LH. In PCOS, the combined effect of body mass index (negative) and testosterone (positive) predicted LH. The best predictor of LH was body mass index and insulin combined. Basal LH and LH responses to GnRH were unaltered by insulin infusion in normal women. These measures were reduced during insulin infusion in PCOS women. CONCLUSIONS In PCOS, insulin infusion suppresses pituitary response to GnRH. In normal women, insulin negatively correlates with mean LH and suppresses GnRH response at a high infusion rate.
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Affiliation(s)
- Mark A Lawson
- Department of Reproductive Medicine 0674, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674.
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Abstract
PURPOSE OF REVIEW As the prevalence of pediatric obesity escalates, polycystic ovary syndrome is an increasingly common morbidity for adolescent females. This review describes recent insights into the pathophysiology and treatment of polycystic ovary syndrome, with special attention given to the relationship between polycystic ovary syndrome and obesity. RECENT FINDINGS Recent research has elucidated three key concepts in our understanding of polycystic ovary syndrome. First, patients may enter the hyperandrogenism-hyperinsulinism cycle of polycystic ovary syndrome via several pathways, including genetic polymorphisms that affect androgen synthesis, fetal programming that alters lipid and glucose metabolism, and obesity accompanied by insulin resistance. Second, obesity plays a significant role in the pathophysiology of polycystic ovary syndrome by increasing free androgen concentrations through multiple mechanisms. Finally, just as the etiology of polycystic ovary syndrome is multifactorial, successful treatment will probably require a combination of lifestyle modification and therapeutic interventions. SUMMARY Obesity contributes to the pathophysiology of polycystic ovary syndrome and increases the likelihood of associated metabolic and cardiovascular morbidities.
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Affiliation(s)
- Takara Stanley
- MassGeneral Hospital for Children and Harvard Medical School, Boston, Massachusetts 02114, USA.
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Salisbury TB, Binder AK, Nilson JH. Welcoming beta-catenin to the gonadotropin-releasing hormone transcriptional network in gonadotropes. Mol Endocrinol 2008; 22:1295-303. [PMID: 18218726 DOI: 10.1210/me.2007-0515] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
GnRH binds its G-coupled protein receptor, GnRHR, on pituitary gonadotropes and stimulates transcription of Cga, Lhb, and Fshb. These three genes encode two heterodimeric glycoprotein hormones, LH and FSH, that act as gonadotropins by regulating gametogenesis and steroidogenesis in both the testes and ovary. GnRH also regulates transcription of Gnrhr. Thus, regulated expression of Cga, Lhb, Fshb, and Gnrhr provides a genomic signature unique to functional gonadotropes. Steadily increasing evidence now indicates that GnRH regulates transcription of its four signature genes indirectly through a hierarchical transcriptional network that includes distinct subclasses of DNA-binding proteins that comprise the immediate early gene (IEG) family. These IEGs, in turn, confer hormonal responsiveness to the four signature genes. Although the IEGs confer responsiveness to GnRH, they cannot act alone. Instead, additional DNA-binding proteins, including the orphan nuclear receptor steroidogenic factor 1, act permissively to allow the four signature genes to respond to GnRH-induced changes in IEG levels. Emerging new findings now indicate that beta-catenin, a transcriptional coactivator and member of the canonical WNT signaling pathway, also plays an essential role in transducing the GnRH signal by interacting with multiple DNA-binding proteins in gonadotropes. Herein we propose that these interactions with beta-catenin define a multicomponent transcriptional network required for regulated expression of the four signature genes of the gonadotrope, Cga, Lhb, Fshb, and Gnrhr.
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Affiliation(s)
- Travis B Salisbury
- School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-4660, USA
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Henke A, Luetjens CM, Simoni M, Gromoll J. Chorionic gonadotropin beta-subunit gene expression in the marmoset pituitary is controlled by steroidogenic factor 1, early growth response protein 1, and pituitary homeobox factor 1. Endocrinology 2007; 148:6062-72. [PMID: 17872365 DOI: 10.1210/en.2007-0825] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In most mammals, the gonads are under the control of the pituitary gonadotropins LH and FSH. However, in the common marmoset monkey Callithrix jacchus, no LH is detectable in the pituitary but chorionic gonadotropin (CG) instead, normally produced in the placenta. This study investigated the mechanism of CGbeta subunit activation in the pituitary and why humans do not express CG in the pituitary. 5'-Rapid amplification of cDNA ends, EMSA, and promoter-driven luciferase assays performed with the gonadotropic LbetaT2 cells showed that marmoset monkey CGbeta is GnRH responsive and activated similar to human LHbeta by the transcription factors steroidogenic factor 1 (SF1), early growth response protein 1 (Egr1), and pituitary homeobox factor 1 (Pitx1) and displayed a transcriptional start site 7 bp upstream of exon 1. In contrast, the human CGbeta promoter displayed in the binding elements for pituitary homeobox factor 1 and early growth response protein 1 three consensus sequence mismatches, leading to very low activity that could be drastically increased by mutation to the consensus sequences. Vice versa, marmoset CGbeta promoter activity was reduced after introduction of the human CGbeta mismatches. An in vivo study in pregnant marmoset monkeys showed that during pregnancy, there is no significant decrease of pituitary CG production, contrasting human LH down-regulation. In conclusion, pituitary CG production is lacking in humans due to the absence of appropriate DNA-binding elements, which are present in marmosets, thereby enabling GnRH activation of expression. However, during pregnancy of marmosets, pituitary CG expression is not inhibited.
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Affiliation(s)
- Alexander Henke
- Institute of Reproductive Medicine, University Clinic Münster, Domagkstrasse 11, Münster, Germany
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Bibliography. Current world literature. Diabetes and the endocrine pancreas II. Curr Opin Endocrinol Diabetes Obes 2007; 14:329-57. [PMID: 17940461 DOI: 10.1097/med.0b013e3282c3a898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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