1
|
Age-associated changes in gene expression in the anterior pituitary glands of female Japanese black cattle. Mamm Genome 2022; 33:606-618. [PMID: 35838775 DOI: 10.1007/s00335-022-09958-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 06/14/2022] [Indexed: 10/17/2022]
Abstract
Proper functioning of the anterior pituitary (AP) gland is imperative, however, is suppressed by aging via unclear mechanisms. Therefore, we identified differentially expressed genes (DEGs) in the AP glands of Japanese Black young heifers (approximately 22 months old) compared to old cows (approximately 120 months old) via deep sequencing of the transcriptome (RNA-seq) to characterize potentially important pathways. The young and old AP glands expressed 20,171 annotated genes. Of the total transcripts per million, approximately 41.6% and 35.5% were the sum of seven AP hormone genes in young and old AP glands, respectively, with difference observed in the sum between the young and old AP glands (P < 0.05). Moreover, we identified 48 downregulated genes and 218 upregulated genes in old compared to young AP glands (P < 0.01, fold change > 120%). The DEGs included 1 cytokine (AIMP1), 3 growth factors (NRG2, PTN, and TGFB1), 1 receptor-associated protein gene (AGTRAP), and 10 receptor genes, including PRLHR and two orphan G-protein-coupled receptors (GPR156 and GPR176). Metascape analysis of the DEGs revealed "Peptide metabolic process," "Regulation of hormone levels," and "Peptide hormone processing" as enriched pathways. Furthermore, Ingenuity Pathway analysis of the DEGs revealed (1) a network of 24 genes (including GPR156 and PRLHR) named "Neurological disease, organismal injury and abnormalities, and psychological disorders", and (2) two canonical pathways (P < 0.01), namely "Huntington's disease signaling", and "AMPK signaling". Thus, the findings of the current study revealed relevant DEGs, while identifying important pathways that occur during aging in AP glands of female cattle.
Collapse
|
2
|
Camm EJ, Inzani I, De Blasio MJ, Davies KL, Lloyd IR, Wooding FBP, Blache D, Fowden AL, Forhead AJ. Thyroid Hormone Deficiency Suppresses Fetal Pituitary-Adrenal Function Near Term: Implications for the Control of Fetal Maturation and Parturition. Thyroid 2021; 31:861-869. [PMID: 33126831 DOI: 10.1089/thy.2020.0534] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background: The fetal hypothalamic-pituitary-adrenal (HPA) axis plays a key role in the control of parturition and maturation of organ systems in preparation for birth. In hypothyroid fetuses, gestational length may be prolonged and maturational processes delayed. The extent to which the effects of thyroid hormone deficiency in utero on the timing of fetal maturation and parturition are mediated by changes to the structure and function of the fetal HPA axis is unknown. Methods: In twin sheep pregnancies where one fetus was thyroidectomized and the other sham-operated, this study investigated the effect of hypothyroidism on circulating concentrations of adrenocorticotrophic hormone (ACTH) and cortisol, and the structure and secretory capacity of the anterior pituitary and adrenal glands. The relative population of pituitary corticotrophs and the masses of the adrenal zones were assessed by immunohistochemical and stereological techniques. Adrenal mRNA abundances of key steroidogenic enzymes and growth factors were examined by quantitative polymerase chain reaction. Results: Hypothyroidism in utero reduced plasma concentrations of ACTH and cortisol. In thyroid-deficient fetuses, the mass of corticotrophs in the anterior pituitary gland was unexpectedly increased, while the mass of the zona fasciculata and its proportion of the adrenal gland were decreased. These structural changes were associated with lower adrenocortical mRNA abundances of insulin-like growth factor (IGF)-I and its receptor, and key steroidogenic enzymes responsible for glucocorticoid synthesis. The relative mass of the adrenal medulla and its proportion of the adrenal gland were increased by thyroid hormone deficiency in utero, without any change in expression of phenylethanolamine N-methyltransferase or the IGF system. Conclusions: Thyroid hormones are important regulators of the structure and secretory capacity of the pituitary-adrenal axis before birth. In hypothyroid fetuses, low plasma cortisol may be due to impaired adrenocortical growth and steroidogenic enzyme expression, secondary to low circulating ACTH concentration. Greater corticotroph population in the anterior pituitary gland of the hypothyroid fetus indicates compensatory cell proliferation and that there may be abnormal corticotroph capacity for ACTH synthesis and/or impaired hypothalamic input. Suppression of the development of the fetal HPA axis by thyroid hormone deficiency may contribute to the delay in fetal maturation and delivery observed in hypothyroid offspring.
Collapse
Affiliation(s)
- Emily J Camm
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Isabella Inzani
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Miles J De Blasio
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Katie L Davies
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - India R Lloyd
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - F B Peter Wooding
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Dominique Blache
- School of Agriculture and Environment, University of Western Australia, Crawley, Australia
| | - Abigail L Fowden
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alison J Forhead
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| |
Collapse
|
3
|
Zimmer B, Piao J, Ramnarine K, Tomishima MJ, Tabar V, Studer L. Derivation of Diverse Hormone-Releasing Pituitary Cells from Human Pluripotent Stem Cells. Stem Cell Reports 2017; 6:858-872. [PMID: 27304916 PMCID: PMC4912387 DOI: 10.1016/j.stemcr.2016.05.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/07/2016] [Accepted: 05/10/2016] [Indexed: 12/27/2022] Open
Abstract
Human pluripotent stem cells (hPSCs) provide an unlimited cell source for regenerative medicine. Hormone-producing cells are particularly suitable for cell therapy, and hypopituitarism, a defect in pituitary gland function, represents a promising therapeutic target. Previous studies have derived pituitary lineages from mouse and human ESCs using 3D organoid cultures that mimic the complex events underlying pituitary gland development in vivo. Instead of relying on unknown cellular signals, we present a simple and efficient strategy to derive human pituitary lineages from hPSCs using monolayer culture conditions suitable for cell manufacturing. We demonstrate that purified placode cells can be directed into pituitary fates using defined signals. hPSC-derived pituitary cells show basal and stimulus-induced hormone release in vitro and engraftment and hormone release in vivo after transplantation into a murine model of hypopituitarism. This work lays the foundation for future cell therapy applications in patients with hypopituitarism. Defined, cGMP-ready protocol to derive anterior pituitary-lineage cells from hPSCs FGF8 and BMP2 patterning enables enrichment for specific hormone-producing cells Pituitary cells secrete multiple hormones and respond to physiological stimuli hPSC-pituitary cells partially rescue a rat model of hypopituitarism
Collapse
Affiliation(s)
- Bastian Zimmer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; Developmental Biology Program, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA
| | - Jinghua Piao
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Kiran Ramnarine
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; SKI Stem Cell Research Facility, 1275 York Avenue, New York, NY 10065, USA
| | - Mark J Tomishima
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; SKI Stem Cell Research Facility, 1275 York Avenue, New York, NY 10065, USA
| | - Viviane Tabar
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Lorenz Studer
- The Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; Developmental Biology Program, Sloan Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA; Department of Neurosurgery, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA.
| |
Collapse
|
4
|
Saloustros E, Salpea P, Starost M, Liu S, Faucz FR, London E, Szarek E, Song WJ, Hussain M, Stratakis CA. Prkar1a gene knockout in the pancreas leads to neuroendocrine tumorigenesis. Endocr Relat Cancer 2017; 24:31-40. [PMID: 27803029 PMCID: PMC5123945 DOI: 10.1530/erc-16-0443] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 10/25/2016] [Indexed: 11/08/2022]
Abstract
Carney complex (CNC) is a rare disease associated with multiple neoplasias, including a predisposition to pancreatic tumors; it is caused most frequently by the inactivation of the PRKAR1A gene, a regulator of the cyclic AMP (cAMP)-dependent kinase (PKA). The method used was to create null alleles of prkar1a in mouse cells expressing pdx1 (Δ-Prkar1a). We found that these mice developed endocrine or mixed endocrine/acinar cell carcinomas with 100% penetrance by the age of 4-5 months. Malignant behavior of the tumors was seen as evidenced by stromal invasion and metastasis to locoregional lymph nodes. Histologically, most tumors exhibited an organoid pattern as seen in the islet-cell tumors. Biochemically, the lesions exhibited high PKA activity, as one would expect from deleting prkar1a The primary neuroendocrine nature of these tumor cells was confirmed by immunohistochemical staining and electron microscopy, the latter revealing the characteristic granules. Although the Δ-Prkar1a mice developed hypoglycemia after overnight fasting, insulin and glucagon levels in the plasma were normal. Negative immunohistochemical staining for the most commonly produced peptides (insulin, c-peptide, glucagon, gastrin and somatostatin) suggested that these tumors were non-functioning. We hypothesize that the recently identified multipotent pdx1+/insulin- cell in adult pancreas, gives rise to endocrine or mixed endocrine/acinar pancreatic malignancies with complete prkar1a deficiency. In conclusion, this mouse model supports the role of prkar1a as a tumor suppressor gene in the pancreas and points to the PKA pathway as a possible therapeutic target for these lesions.
Collapse
Affiliation(s)
- Emmanouil Saloustros
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Paraskevi Salpea
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Matthew Starost
- Diagnostic and Research Services BranchDivision of Veterinary Resources (DVR), Office of Research Services (ORS), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Sissi Liu
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Fabio R Faucz
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Edra London
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Eva Szarek
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Woo-Jin Song
- Department of PediatricsMetabolism Division, John Hopkins University, Baltimore, Maryland, USA
| | - Mehboob Hussain
- Department of PediatricsMetabolism Division, John Hopkins University, Baltimore, Maryland, USA
| | - Constantine A Stratakis
- Section on Endocrinology and GeneticsProgram on Developmental Endocrinology & Genetics (PDEGEN) & Pediatric Endocrinology Inter-institute Training Program, Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| |
Collapse
|
5
|
Weltzien FA, Hildahl J, Hodne K, Okubo K, Haug TM. Embryonic development of gonadotrope cells and gonadotropic hormones--lessons from model fish. Mol Cell Endocrinol 2014; 385:18-27. [PMID: 24145126 DOI: 10.1016/j.mce.2013.10.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/30/2013] [Accepted: 10/11/2013] [Indexed: 01/05/2023]
Abstract
Pituitary gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), are key regulators of vertebrate reproduction. The differential regulation of these hormones, however, is poorly understood and little is known about gonadotrope embryonic development. The different cell types in the vertebrate pituitary develop from common progenitor cells just after gastrulation. Proper development and merging of the anterior and posterior pituitary is dependent upon carefully regulated cell-to-cell interactions, and a suite of signaling pathways with precisely organized temporal and spatial expression patterns, which include transcription factors and their co-activators and repressors. Among the pituitary endocrine cell types, the gonadotropes are the last to develop and become functional. Although much progress has been made during the last decade regarding details of gonadotrope development, the coordinated program for their maturation is not well described. FSH and LH form an integral part of the hypothalamo-pituitary-gonad axis, the main regulator of gonad development and reproduction. Besides regulating gonad development, pre- and early post-natal activity in this axis is thought to be essential for proper development, especially of the central nervous system in mammals. As a means to investigate early functions of FSH and LH in more detail, we have developed a stable transgenic line of medaka with the LH beta subunit gene (lhb) promoter driving green fluorescent protein (Gfp) expression to characterize development of lhb-expressing gonadotropes. The lhb gene is maternally expressed early during embryogenesis. lhb-Expressing cells are initially localized outside the primordial pituitary in the developing gut tube as early as 32 hpf. At hatching, lhb-Gfp is clearly detected in the gut epithelium and in the anterior digestive tract. lhb-Gfp expression later consolidates in the developing pituitary by 2 weeks post-fertilization. This review discusses status of knowledge regarding pituitary morphology and development, with emphasis on gonadotrope cells and gonadotropins during early development, comparing main model species like mouse, zebrafish and medaka, including possible developmental functions of the observed extra pituitary expression of lhb in medaka.
Collapse
Affiliation(s)
- Finn-Arne Weltzien
- Department of Basic Sciences and Aquatic Medicine, Weltzien Laboratory, Norwegian School of Veterinary Science, Oslo, Norway; Department of Biosciences, University of Oslo, Oslo, Norway.
| | - Jon Hildahl
- Department of Basic Sciences and Aquatic Medicine, Weltzien Laboratory, Norwegian School of Veterinary Science, Oslo, Norway; Department of Biosciences, University of Oslo, Oslo, Norway
| | - Kjetil Hodne
- Department of Basic Sciences and Aquatic Medicine, Weltzien Laboratory, Norwegian School of Veterinary Science, Oslo, Norway
| | - Kataaki Okubo
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Trude M Haug
- Department of Biosciences, University of Oslo, Oslo, Norway
| |
Collapse
|
6
|
Sandhu MA, Saeed AA, Khilji MS, Pasha RH, Mukhtar N, Anjum MS. Ontogenic development of corticotrophs in fetal buffalo (Bubalus bubalis) pituitary gland. Eur J Histochem 2014; 58:2292. [PMID: 24704996 PMCID: PMC3980209 DOI: 10.4081/ejh.2014.2292] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/02/2013] [Accepted: 12/03/2013] [Indexed: 11/23/2022] Open
Abstract
To evaluate the subpopulation of corticotrophs in developing buffalo (Bubalus bubalis) fetus, pituitary glands were recovered (n=6 per group) from late first, second and third gestational female buffalo dams. The corticotrophs were identified by using specific antibodies against proopiomelanocortin (POMC) and adrenocorticotrophic hormone (ACTH) through immunohistochemistry. There was a significant (P≤0.05) increase of immunoreactive (ir) ir-ACTH cells during late 2nd trimester while, ir-POMC cells were more (P≤0.05) at late 3rd trimester of gestation as compared to other age groups. The quantity of co-localized cells for POMC and ACTH was significantly (P≤0.05) greater at the end of 1st gestation rather than 2nd and 3rd gestational fetal adenohypophyseal cells. This study is the first to demonstrate co-localization of POMC+ACTH and the affect of gestational age on the expression of these cells in buffalo fetus adenohypophysis.
Collapse
Affiliation(s)
- M A Sandhu
- PMAS, Arid Agriculture University, Rawalpindi.
| | | | | | | | | | | |
Collapse
|
7
|
Dietrich JW, Landgrafe G, Fotiadou EH. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis. J Thyroid Res 2012; 2012:351864. [PMID: 23365787 PMCID: PMC3544290 DOI: 10.1155/2012/351864] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/21/2012] [Indexed: 12/11/2022] Open
Abstract
This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range.
Collapse
Affiliation(s)
- Johannes W. Dietrich
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
| | - Gabi Landgrafe
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
- Klinik für Allgemein- und Visceralchirurgie, Agaplesion Bethesda Krankenhaus Wuppertal gGmbH, Hainstraße 35, 42109 Wuppertal, NRW, Germany
| | - Elisavet H. Fotiadou
- Lab XU44, Medical Hospital I, Bergmannsheil University Hospitals, Ruhr University of Bochum (UK RUB), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, NRW, Germany
| |
Collapse
|
8
|
Hildahl J, Sandvik GK, Lifjeld R, Hodne K, Nagahama Y, Haug TM, Okubo K, Weltzien FA. Developmental tracing of luteinizing hormone β-subunit gene expression using green fluorescent protein transgenic medaka (Oryzias latipes) reveals a putative novel developmental function. Dev Dyn 2012; 241:1665-77. [DOI: 10.1002/dvdy.23860] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2012] [Indexed: 11/06/2022] Open
|
9
|
Gonzalez B, Ratner LD, Di Giorgio NP, Poutanen M, Huhtaniemi IT, Calandra RS, Lux-Lantos VAR, Rulli SB. Endogenously elevated androgens alter the developmental programming of the hypothalamic-pituitary axis in male mice. Mol Cell Endocrinol 2011; 332:78-87. [PMID: 20933053 DOI: 10.1016/j.mce.2010.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/14/2010] [Accepted: 09/28/2010] [Indexed: 01/09/2023]
Abstract
Transgenic male mice that express human chorionic gonadotropin (hCG) α and β subunits constitutively hypersecrete hCG and produce elevated levels of androgens. The aim of this study was to characterize the hypothalamic-pituitary function of these transgenic (hCGαβ+) males by focusing on FSH regulation. Serum FSH levels and pituitary mRNA expression of Fshb, Lhb, Cga, Gnrhr and Esr1 were reduced, whereas Fst expression was increased in prepubertal hCGαβ+ males as compared with wild-type. In the hypothalamus, Cyp19a1 expression, GnRH concentration and ex-vivo GnRH pulsatility were elevated in prepubertal hCGαβ+ mice, whereas Kiss1 expression was decreased prepubertally and Gad67 expression was elevated neonatally. The effect of androgens on the developmental programming of the hypothalamic-pituitary axis of hCGαβ+ males was evaluated by perinatal and prepubertal antiandrogen (flutamide) administration. Our studies identified a critical window between gestational day 18 and postnatal day 14, during which chronically elevated androgens and/or their locally produced metabolites activate the hypothalamus and concomitantly shut-down the gonadotropin axis.
Collapse
Affiliation(s)
- Betina Gonzalez
- Instituto de Biología y Medicina Experimental-CONICET, Vuelta de Obligado 2490 (1428), Buenos Aires, Argentina
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Embryonic gonadotropin-releasing hormone signaling is necessary for maturation of the male reproductive axis. Proc Natl Acad Sci U S A 2010; 107:16372-7. [PMID: 20805495 DOI: 10.1073/pnas.1000423107] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gonadotropin-releasing hormone (GnRH) signaling regulates reproductive physiology in mammals. GnRH is released by a subset of hypothalamic neurons and binds to GnRH receptor (GnRHR) on gonadotropes in the anterior pituitary gland to control production and secretion of gonadotropins that in turn regulate the activity of the gonads. Central control of reproduction is well understood in adult animals, but GnRH signaling has also been implicated in the development of the reproductive axis. To investigate the role of GnRH signaling during development, we selectively ablated GnRHR-expressing cells in mice. This genetic strategy permitted us to identify an essential stage in male reproductive axis development, which depends on embryonic GnRH signaling. Our experiments revealed a striking dichotomy in the gonadotrope population of the fetal anterior pituitary gland. We show that luteinizing hormone-expressing gonadotropes, but not follicle-stimulating hormone-expressing gonadotropes, express the GnRHR at embryonic day 16.75. Furthermore, we demonstrate that an embryonic increase in luteinizing hormone secretion is needed to promote development of follicle-stimulating hormone-expressing gonadotropes, which might be mediated by paracrine interactions within the pituitary. Moreover, migration of GnRH neurons into the hypothalamus appeared normal with appropriate axonal connections to the median eminence, providing genetic evidence against autocrine regulation of GnRH neurons. Surprisingly, genetic ablation of GnRHR expressing cells significantly increased the number of GnRH neurons in the anterior hypothalamus, suggesting an unexpected role of GnRH signaling in establishing the size of the GnRH neuronal population. Our experiments define a functional role of embryonic GnRH signaling.
Collapse
|