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Jiménez-Díaz E, Del-Rio D, Fiordelisio T. The Contribution of Cell Imaging to the Study of Anterior Pituitary Function and Its Regulation. Neuroendocrinology 2023; 113:179-192. [PMID: 35231920 DOI: 10.1159/000523860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 02/18/2022] [Indexed: 11/19/2022]
Abstract
Advances in the knowledge of the neuroendocrine system are closely related to the development of cellular imaging and labeling techniques. This synergy ranges from the staining techniques that allowed the first characterizations of the anterior pituitary gland, its relationship with the hypothalamus, and the birth of neuroendocrinology; through the development of fluorescence microscopy applications, specific labeling strategies, transgenic systems, and intracellular calcium sensors that enabled the study of processes and dynamics at the cellular and tissue level; until the advent of super-resolution microscopy, miniscopes, optogenetics, fiber photometry, and other imaging methods that allowed high spatiotemporal resolution and long-term three-dimensional cellular activity recordings in living systems in a conscious and freely moving condition. In this review, we briefly summarize the main contributions of cellular imaging techniques that have allowed relevant advances in the field of neuroendocrinology and paradigm shifts that have improved our understanding of the function of the hypothalamic-pituitary axes. The development of these methods and equipment is the result of the integration of knowledge achieved by the integration of several disciplines and effort to solve scientific questions and problems of high impact on health and society that this system entails.
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Affiliation(s)
- Edgar Jiménez-Díaz
- Laboratorio de Neuroendocrinología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Diana Del-Rio
- Laboratorio de Neuroendocrinología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Tatiana Fiordelisio
- Laboratorio de Neuroendocrinología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Laboratorio Nacional de Soluciones Biomiméticas para Diagnóstico y Terapia LaNSBioDyT, Universidad Nacional Autónoma de México, Mexico City, Mexico
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2
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Fontaine R, Rahmad Royan M, Henkel C, Hodne K, Ager-Wick E, Weltzien FA. Pituitary multi-hormone cells in mammals and fish: history, origin, and roles. Front Neuroendocrinol 2022; 67:101018. [PMID: 35870647 DOI: 10.1016/j.yfrne.2022.101018] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/10/2022] [Accepted: 07/18/2022] [Indexed: 11/04/2022]
Abstract
The vertebrate pituitary is a dynamic organ, capable of adapting its hormone secretion to different physiological demands. In this context, endocrinologists have debated for the past 40 years if endocrine cells are mono- or multi-hormonal. Since its establishment, the dominant "one cell, one hormone" model has been continuously challenged. In mammals, the use of advanced multi-staining approaches, sensitive gene expression techniques, and the analysis of tumor tissues have helped to quickly demonstrate the existence of pituitary multi-hormone cells. In fishes however, only recent advances in imaging and transcriptomics have enabled the identification of such cells. In this review, we first describe the history of the discovery of cells producing multiple hormones in mammals and fishes. We discuss the technical limitations that have led to uncertainties and debates. Then, we present the current knowledge and hypotheses regarding their origin and biological role, which provides a comprehensive review of pituitary plasticity.
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Affiliation(s)
- Romain Fontaine
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
| | - Muhammad Rahmad Royan
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Christiaan Henkel
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Kjetil Hodne
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Eirill Ager-Wick
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Finn-Arne Weltzien
- Department of Preclinical Sciences and Pathology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
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3
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Trifunović S, Milošević V. The Morpho-Functional Parameters of Rat Pituitary Hormone Producing Cells After Genistein Treatment. MACEDONIAN VETERINARY REVIEW 2018. [DOI: 10.1515/macvetrev-2017-0027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Abstract
Phytoestrogens are a diverse group of steroid–like compounds that occur naturally in many plants. There are various types of phytoestrogens, including the best-researched isoflavones which are commonly found in soy. The consumption of soy products has many health benefits, including protection against breast cancer, prostate cancer, menopausal symptoms, heart disease and osteoporosis. In contrast, use of hormonally active compounds-isoflavones may unfortunately interfere with the endocrine system and can have far-reaching consequences. Genistein, the most abundant soy-bean derived isoflavone, possesses a ring system similar to estrogens and acts through an estrogen receptor (ER)-mediated mechanism, by increasing or decreasing the transcription of ER-dependent target genes. Also, genistein can act on cells through ER non-dependent mechanisms, such as tyrosine kinase inhibitor. The neuroendocrine systems are responsible for the control of homeostatic processes in the body, including reproduction, growth, metabolism and energy balance, and stress responsiveness. It is well known, that estrogen is important for development of the neuroendocrine system in both sexes. At the pituitary level, estrogen is known to affect the regulation of all hormone producing (HP) cells, by direct and/or indirect mechanisms. Due to structural and functional resemblance to estrogen, the question may arise of whether and how genistein affects the morphofunctional features of pituitary HP cells. This review deals with the consequences of genistein’s effects on morphological, stereological and hormonal features of HP cells within the anterior pituitary gland. Transparency on this issue is needed because isoflavones are presently highly consumed. Inter alia, genistein as well as other isoflavones, are present in various dietary supplements and generally promoted as an accepted alternative to estrogen replacement therapy. Potential isoflavone biomedical exploitation is not only limited to estrogen replacement therapy, so it should be treated in a wider context of different ageing symptoms remediation.
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Affiliation(s)
- Svetlana Trifunović
- Department of Cytology, Institute for Biological Research “Siniša Stanković” , University of Belgrade , Bul Despot Stefan 142, 11060 Belgrade , Serbia
| | - Verica Milošević
- Department of Cytology, Institute for Biological Research “Siniša Stanković” , University of Belgrade , Bul Despot Stefan 142, 11060 Belgrade , Serbia
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Cheng Y, Xiang Y, Lin Y, Fu S, Jia W, Zhang G, Lv W, Mi S, Zhao Q. Retinoic acid and dexamethasone induce differentiation and maturation of somatotroph cells at different stages in vitro. Endocr J 2011; 58:177-84. [PMID: 21350304 DOI: 10.1507/endocrj.k10e-315] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The purpose of this study was to investigate the role of retinoic acid (RA) and/or dexamethasone and growth hormone releasing hormone (GHRH) in the induction of somatotroph cell differentiation. Immunohistochemistry, radioimmunoassay, 3-(4,5-dimethylthiazol -1,2-y1)-2,5-diphenyltetrazolium bromide assay, and immune electron microscopy were employed to determine the effect of incubation with these constituents on the differentiation into somatotrophs of cells isolated from the rat embryonic pituitary gland. RA administration increased the proportion of growth hormone (GH) positive somatotroph cells and GH secretion in embryonic pituitary cells (P<0.01). After 4 days of incubation with RA, additional administration of dexamethasone further increased the proportion of somatotroph cells and GH secretion (P<0.01), and increased the number of secretory granules in the somatotroph cells. Addition of GHRH alone had no such effect (P>0.05). However, addition of GHRH to treatment with RA plus dexamethasone significantly increased both the proportion of somatotroph cells and the secretion of GH compared to treatment with RA or dexamethasone alone or RA plus dexamethasone (P<0.01). RA promoted the early differentiation of somatotroph cells, dexamethasone promoted the differentiation and maturation of somatotroph cells and in addition, RA, dexamethasone and GHRH together exerted synergistic effects that markedly promoted somatotroph cell differentiation, maturation and GH secretion.
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Affiliation(s)
- Yu Cheng
- The Department of Neurological Surgery, First Affiliated Hospital, Harbin Medical University, Harbin, P.R.China
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Pals K, Roudbaraki M, Denef C. Growth hormone-releasing hormone and glucocorticoids determine the balance between luteinising hormone (LH) beta- and LH beta/follicle-stimulating hormone beta-positive gonadotrophs and somatotrophs in the 14-day-old rat pituitary tissue in aggregate cell culture. J Neuroendocrinol 2008; 20:535-48. [PMID: 18363807 DOI: 10.1111/j.1365-2826.2008.01698.x] [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] [Indexed: 11/28/2022]
Abstract
Fourteen-day-old rat pituitary tissue represents an attractive model for studying cell population dynamics, particularly of gonadotrophs. Prolonged three-dimensional culture in serum- and hormone-free medium causes a striking decline in somatotroph abundance but a several-fold rise in monohormonal LH beta-positive cell number, whereas bihormonal gonadotrophs almost disappear. In the present study, we investigated whether these changes are inter-related by examining the effects of growth hormone-releasing hormone (GHRH) and glucocorticoids, two protagonist regulators of somatotrophs. Cells were identified by single cell reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence. Supplementation of the cultures for 2 weeks with GHRH (1 nm) did not augment the proportion of somatotrophs, but expanded the nonhormonal cell population. GHRH reduced the proportion of monohormonal luteinising hormone (LH)beta mRNA positive cells to approximately 50% of control, although the effect was not seen when these cells were visualised by immunostaining. Supplementation of the cultures with dexamethasone (4 nM) for 3 weeks partially rescued LH beta/follicle-stimulating hormone beta cells and fully rescued the GH mRNA cells in parallel with a decline in nonhormonal cell abundance, but strongly reduced bromodeoxyuridine labelling of GH-immunoreactive cells. As studied by patch-clamp single cell RT-PCR at the start of culture, GHRH caused an acute rise in intracellular [Ca(2+)] in some monohormonal GH cells, but at a higher incidence in cells expressing LH beta mRNA, alone or in combination with GH mRNA and/or pro-opiomelanocortin (POMC) mRNA. The present data suggest that, in the 14-day-old rat pituitary, the majority of GHRH target cells are cells expressing LH beta mRNA alone or in combination with GH and/or POMC mRNA. The data show co-regulation of gonadotroph and somatotroph population sizes by glucocorticoids and GHRH, with the former preserving bihormonal gonadotrophs and the latter repressing LH beta-only cell abundance. GHRH may not expand the somatotroph population unless glucocorticoid hormone is present to maintain terminal differentiation.
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Affiliation(s)
- K Pals
- Laboratory of Cell Pharmacology, University of Leuven, Medical School, Campus Gasthuisberg (O&N), Leuven, Belgium
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6
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Papageorgiou A, Denef C. Stimulation of growth hormone release by 5-hydroxytryptamine (5-HT) in cultured rat anterior pituitary cell aggregates: evidence for mediation by 5-HT2B, 5-HT7, 5-HT1B, and ketanserin-sensitive receptors. Endocrinology 2007; 148:4509-22. [PMID: 17584957 DOI: 10.1210/en.2007-0034] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
5-Hydroxytryptamine (5-HT) promotes the release of GH by a hypothalamic site of action. The present study explores a putative pituitary action in a perifused rat anterior pituitary aggregate cell culture system. In aggregates cultured with 1 nM estradiol for expression of the 5-HT4, -5, and -6 receptor (R), 5-HT promptly stimulated GH secretion with a dose dependency between 1 and 10 nM. The effect of 5-HT was partially blocked by methiothepin and methysergide; by SB-206553, a 5-HTR2B/C antagonist; SB-269970, a 5-HTR7/5A antagonist; and SB-224289, a 5-HTR1B antagonist. The GH response was fully blocked by combined administration of SB-206553+SB-269970 and SB-206553+ketanserin but not by SB-206553+spiperone. Culturing the aggregates without estradiol diminished the magnitude of the GH response to 5-HT as well as the impact of 5-HTR7/5 blockade on the response. Basal GH release was stimulated by the 5-HTR2 agonists 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, m-chlorophenyl piperazine, and alpha-methyl 5-HT; 5-carboxytryptamine (agonist at 5-HTR1, -5, and -7); tryptamine (preferential 5-HTR7 agonist); and the selective 5-HTR1B agonist CP93129 but not the 5-HTR1A agonists 7-(dipropylamino)tetralin-1-ol-8-hydroxy-2-(di-n-propylamino)tetralin and the 5-HTR1B/D agonist sumatriptan. The selective 5-HTR2B agonist BW 723C86 stimulated GH release, and the selective 5-HTR2B antagonist SB-204741 attenuated the GH response to 5-HT. The present data suggest that 5-HT may release GH through a pituitary site of action, and that the 5-HTR2B, 5-HTR7 and 5-HTR1B mediate this response, with possibly an inhibitory component of the 5-HTR1D. The relative contribution of these receptors may be modulated by estrogen.
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MESH Headings
- Animals
- Cell Aggregation
- Cells, Cultured
- Growth Hormone/metabolism
- Ketanserin/pharmacology
- Pituitary Gland, Anterior/cytology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/physiology
- Rats
- Receptor, Serotonin, 5-HT2B/drug effects
- Receptor, Serotonin, 5-HT2B/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Serotonin/pharmacology
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Affiliation(s)
- A Papageorgiou
- Laboratory of Cell Pharmacology, University of Leuven, Medical School, Campus Gasthuisberg (O and N), B-3000 Leuven, Belgium
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7
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Abstract
Tissue-specific stem cells are uncovered in a growing number of organs by their molecular expression profile and their potential for self-renewal, multipotent differentiation and tissue regeneration. Whether the pituitary gland also contains a pool of versatile 'master' cells that drive homeostatic, plastic and regenerative cell ontogenesis is at present unknown. Here, I will give an overview of data that may lend support to the existence of stem cells in the postnatal pituitary. During the many decades of pituitary research, various approaches have been used to hunt for the pituitary stem cells. Transplantation and regeneration studies advanced chromophobes as possible source of new hormonal cells. Clonogenicity approaches identified pituitary cells that clonally expand to floating spheres, or to colonies in adherent cell cultures. Behavioural characteristics and changes of marginal, follicular and folliculostellate cells during defined developmental and (patho-)physiological conditions have been interpreted as indicative of a stem cell role. Expression of potential stem cell markers like nestin, as well as topographical localization in the marginal zone around the cleft has also been considered to designate pituitary stem cells. Finally, a 'side population' was recently identified in the postnatal pituitary which in many other tissues represents a stem cell-enriched fraction. Taken together, in the course of the long-standing study of the pituitary, several arguments have been presented to support the existence of stem cells, and multiple cell types have been placed in the spotlight as possible candidates. However, none of these cells has until now unequivocally been shown to meet all quintessential characteristics of stem cells.
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Affiliation(s)
- Hugo Vankelecom
- Laboratory of Cell Pharmacology, Department of Molecular Cell Biology, University of Leuven, Leuven, Belgium.
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8
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Denef C, Pals K, Hauspie A, Vankelecom H, Seuntjens E. Combinatorial expression of phenotypes of different cell lineages in the rat and mouse pituitary. Ann N Y Acad Sci 2006; 1040:84-8. [PMID: 15891010 DOI: 10.1196/annals.1327.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
As studied by single cell RT-PCR of pituitary hormones, we demonstrated that the pituitaries of rats and mice contain a subpopulation of cells that express two or more hormone phenotypes typically belonging to lineages that are branched separately early during embryonic development, such as glycoprotein hormone alpha-subunit (alphaGSU) mRNA + PRL mRNA, alphaGSU mRNA + POMC mRNA, and POMC mRNA + GH or PRL mRNA. GnRH in vitro selectively expands the population of cells coexpressing alphaGSU mRNA + PRL mRNA, and CRH selectively increases the proportion of cells coexpressing alphaGSU mRNA + POMC mRNA. Colocalization of alphaGSU + PRL or alphaGSU + POMC could not be detected by double immunofluorescence. This lineage promiscuity was also observed in the pituitary in vivo.
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Affiliation(s)
- C Denef
- Laboratory of Cell Pharmacology, University of Leuven, School of Medicine, Belgium.
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9
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Childs GV, Iruthayanathan M, Akhter N, Johnson BW. Estrogen mediated cross talk between the ovary and pituitary somatotrope. Pre-ovulatory support for reproductive activity. Mol Cell Endocrinol 2006; 247:60-3. [PMID: 16443322 PMCID: PMC1751516 DOI: 10.1016/j.mce.2005.12.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 12/13/2005] [Accepted: 12/14/2005] [Indexed: 11/16/2022]
Affiliation(s)
- Gwen V Childs
- Department of Neurobiology and Developmental Sciences, College of Medicine, 4301 W. Markham, Slot 510, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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10
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Pals K, Vankelecom H, Denef C. Triiodothyronine expands the lactotroph and maintains the lactosomatotroph population, whereas thyrotrophin-releasing hormone augments thyrotroph abundance in aggregate cell cultures of postnatal rat pituitary gland. J Neuroendocrinol 2006; 18:203-16. [PMID: 16454804 DOI: 10.1111/j.1365-2826.2005.01404.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In the present study, we used a three-dimensional pituitary cell culture system from early postnatal rats to examine the in vitro developmental potential of triiodothyronine (T3) and thyrotrophin-releasing hormone (TRH). Cell types were identified at the hormone mRNA level by single-cell reverse transcription-polymerase chain reaction and any change in abundance was further examined by immunofluorescence staining of the corresponding hormone protein. In aggregates from 14-day-old rats, long-term (12-16 days) treatment with T3 (0.5 nM) increased the abundance of cells expressing prolactin mRNA (PRLmRNA cells) by 2.5-fold and lowered that of nonhormonal cells and thyroid-stimulating hormone beta (TSHbeta)mRNA cells. The abundance of growth hormone (GH)mRNA cells decreased during culture compared to that in the freshly dispersed pituitary gland and T3 did not significantly affect this cell population. Cells coexpressing PRL mRNA and GH mRNA virtually disappeared during culture but reappeared in the presence of T3. T3 increased the abundance of PRL-immunoreactive (ir) cells in aggregates from 14-day-old rats, as well as in aggregates from newborn and 1-week-old rats. As estimated by bromodeoxyuridine (BrdU) labelling, a 3-day treatment with T3 enhanced the number of PRL-ir cells that had incorporated BrdU, but did not yet expand the total population of PRL-ir cells. Long-term treatment with TRH (100 nM) did not affect the proportion of PRLmRNA or GHmRNA cells, but consistently increased the proportional number of TSHbeta(mRNA) and TSHbeta-ir cells. The present data confirm the findings obtained in recent in vivo loss of function genetic studies suggesting that T3 plays a prominent role in postnatal expansion of the lactotroph population and that TRH is important for thyrotroph development. The data suggest that the effect of T3 is brought about by a direct action on the pituitary gland through a cell proliferation mechanism. T3 also appears to support the lactosomatotroph population. In view of the established theory that lactotrophs develop from GH-expressing progenitor cells and that this is a post mitotic event, we propose that T3 is mitogenic for GHmRNA cells that lack GH-ir material and that transdifferentiate into PRL-ir cells, but that a pathway of PRL cell development from mitotic nonhormonal cell progenitors may also be involved.
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Affiliation(s)
- K Pals
- Laboratory of Cell Pharmacology, University of Leuven (K.U.Leuven), Medical School, Campus Gasthuisberg (O & N), B-3000, Leuven, Belgium
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11
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Shukuwa K, Izumi SI, Hishikawa Y, Ejima K, Inoue S, Muramatsu M, Ouchi Y, Kitaoka T, Koji T. Diethylstilbestrol increases the density of prolactin cells in male mouse pituitary by inducing proliferation of prolactin cells and transdifferentiation of gonadotropic cells. Histochem Cell Biol 2006; 126:111-23. [PMID: 16468032 DOI: 10.1007/s00418-005-0141-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2005] [Indexed: 10/25/2022]
Abstract
Diethylstilbestrol (DES) has been implicated in mammalian abnormalities. We examined the effects of DES on follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin (PRL) cells in the pituitaries of male mice treated with various doses of DES for 20 days. DES reduced the density of FSH and LH cells in a dose-dependent manner, but increased that of PRL cells. When the expression of estrogen receptor (ER) alpha and beta was assessed, an induction of ERbeta by DES was found predominantly in PRL cells. However, since these effects were abolished in ERalpha knockout mice, DES appears to act primarily through ERalpha. When the expression of Ki-67 and Pit-1 in PRL cells was examined at various time-points after DES treatment, some PRL cells became Ki-67 positive at 10-15 days, and Pit-1-positive cells were increased at 5-15 days. Furthermore, some FSH and LH cells became Pit-1 positive, and co-localized with PRL at 5-10 days. Our results indicate that DES increases PRL cells by inducing proliferation of PRL cells and transdifferentiation of FSH/LH cells to PRL cells.
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Affiliation(s)
- Keiko Shukuwa
- Division of Histology and Cell Biology, Department of Developmental and Reconstructive Medicine, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, 852-8523, Nagasaki, Japan
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12
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Swinnen E, Boussemaere M, Denef C. Stimulation and inhibition of prolactin release by prolactin-releasing Peptide in rat anterior pituitary cell aggregates. J Neuroendocrinol 2005; 17:379-86. [PMID: 15929743 DOI: 10.1111/j.1365-2826.2005.01313.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although the G-protein coupled receptor GPR10 is highly expressed in the anterior pituitary, the action of its ligand prolactin-releasing peptide-31 (PrRP) in this tissue is controversial. The present study examined the acute effect of this peptide on prolactin secretion in perifused rat pituitary reaggregate cell cultures from adult male rats. PrRP readily and dose-dependently stimulated prolactin release at concentrations of 10 and 100 nM, although with a magnitude several times lower than that of thyrotropin-releasing hormone. Surprisingly, PrRP inhibited prolactin release at 0.1 and 1 nm in a pertussis toxin-sensitive manner. Inhibition was markedly favoured by long-term culture. Stimulation and inhibition were differentially affected by the presence of hormones during culture: dexamethasone favoured the inhibitory effect and decreased the magnitude of the stimulatory effect, while oestradiol and triiodothyronine strongly reduced stimulation, as well as inhibition. PrRP, even at 1 nm, counteracted the inhibition of prolactin release by dopamine. There was no effect of PrRP on growth hormone release in aggregates cultured either in the absence or presence of hormones. The present results confirm the prolactin-releasing capacity of PrRP at nanomolar doses and reveal a hitherto unrecognized inhibitory activity of this peptide. Furthermore, dopamine inhibition of prolactin release is antagonized by PrRP, irrespective of the PrRP dose.
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Affiliation(s)
- E Swinnen
- Laboratory of Cell Pharmacology, University of Leuven, Medical School, Campus Gasthuisberg, Belgium
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13
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Villalobos C, Núñez L, García-Sancho J. Phenotypic characterization of multi-functional somatotropes, mammotropes and gonadotropes of the mouse anterior pituitary. Pflugers Arch 2005; 449:257-64. [PMID: 15378370 DOI: 10.1007/s00424-004-1337-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The existence of bihormonal anterior pituitary (AP) cells co-storing growth hormone and either prolactin (mammosomatotrope) or gonadotropins (somatogonadotrope) has been described. These cells have been proposed to be involved in "paradoxical" secretion [secretion of an AP hormone induced by a non-related hypothalamic releasing factor (HRH) and transdifferentiation (a phenotypic switch between different cell types without cell division]. Here we combine calcium imaging (to assess HRH responsiveness) and multiple sequential immunoassay of the six AP hormones to perform a single-cell phenotypic study of multifunctional somatotropes, mammotropes and gonadotropes in the normal male and female mouse pituitaries. AP cell phenotypes differed from the classic view, showing multiple HRH-receptor expression and/or hormone storage. Mammosomatotropes represented only 5-6% of somatotropes and were poorly responsive to HRHs, suggesting that their contribution to paradoxical secretion should be very limited. Somatogonadotropes were present only in females and contained adrenocorticotropic hormone. They responded to growth hormone-releasing hormone but failed to respond to gonadotropin-releasing hormone (LHRH). Other polyhormonal cells identified include (1) gonadocorticotropes, restricted to females, where they make up more than 50% of all the gonadotropes and contain other AP hormones; (2) gonadomammotropes, which are present preferentially in female cells and respond to LHRH; and (3) gonadothyrotropes, which are present similarly in male and female pituitaries.
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Affiliation(s)
- Carlos Villalobos
- Departamento de Fisiología y Bioquímica, Facultad de Medicina, Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Cientificas (CSIC), Ramón y Cajal 7, 47005 Valladolid, Spain
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14
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Childs GV, Iruthayanathan M, Akhter N, Unabia G, Whitehead-Johnson B. Bipotential effects of estrogen on growth hormone synthesis and storage in vitro. Endocrinology 2005; 146:1780-8. [PMID: 15618363 PMCID: PMC1751515 DOI: 10.1210/en.2004-1111] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Increased pulses of serum GH coincide with rising estrogens during the reproductive cycle, suggesting estrogen regulation. However, there is lack of agreement about estrogen's direct effects on the pituitary. Pituitaries from cycling female rats were dispersed and plated for 24 h in defined media containing vehicle or 0.001-250 nm 17beta-estradiol. Estrogen (0.01-10 nm) increased the percentages of GH antigen-bearing cells in the anterior pituitary significantly (1.3- to 1.6-fold) and 0.01-1 nm concentrations also stimulated significant increases in GH mRNA-bearing cells and in the integrated OD for GH mRNA. However, 100-250 nm either had no effect or, inhibitory effects on the area of label for GH mRNA. To test estrogen's effects on expression of GHRH receptors, cultures were stimulated with biotinylated analogs of GHRH and target cells detected by affinity cytochemistry. Estrogen increased GHRH target cells in populations from rats in all stages of the cycle tested. Basal expression of GHRH target cells declined at metestrus. Cultures treated with 0-1 nm estrogen were then dual labeled for bio-GHRH followed by immunolabeling for GH with the antirabbit IgG-ImmPRESS peroxidase polymer. Over 98% of GH cells bound GHRH and 90-96% of GHRH-bound cells contained GH in all treatment groups. Thus, low concentrations of estrogen may stimulate expression of more cells with GH proteins, biotinylated GHRH binding sites, and GH mRNA, whereas high concentrations have no effect, or may reduce GH mRNA. These bipotential effects may help explain the different findings reported in the literature.
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Affiliation(s)
- Gwen V Childs
- Department of Neurobiology and Developmental Sciences, College of Medicine, 4301 West Markham, University of Arkansas for Medical Science, Little Rock, Arkansas 72205, USA.
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Villalobos C, Núñez L, García-Sancho J. Anterior pituitary thyrotropes are multifunctional cells. Am J Physiol Endocrinol Metab 2004; 287:E1166-70. [PMID: 15226100 DOI: 10.1152/ajpendo.00194.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Anterior pituitary (AP) contains some unorthodox multifunctional cells that store and secrete two different AP hormones (polyhormonal cells) and/or respond to several hypothalamic-releasing hormones (HRHs; multiresponsive cells). Multifunctional cells may be involved in paradoxical secretion (secretion of a given AP hormone evoked by a noncorresponding HRH) and transdifferentiation (phenotypic switch between different mature cell types without cell division). Here we combine calcium imaging (to assess responses to the four HRHs) and multiple sequential immunoassay of the six AP hormones to perform a single-cell phenotypic study of thyrotropes in normal male and female mice. Surprisingly, most of the thyrotropes were polyhormonal, containing, in addition to thyrotropin (TSH), luteinizing hormone (40-42%) and prolactin (19-21%). Thyrotropes costoring growth hormone and/or ACTH were found only in females (24% of each type). These results suggest that costorage of the different hormones does not happen at random and that gender favors certain hormone combinations. Our results indicate that thyrotropes are a mosaic of cell phenotypes rather than a single cell type. The striking promiscuity of TSH storage should originate considerable mix-up of AP hormone secretions on stimulation of thyrotropes. However, response to thyrotropin-releasing hormone was much weaker in the polyhormonal thyrotropes than in the monohormonal ones. This would limit the appearance of paradoxical secretion under physiological conditions and suggests that timing of hormone and HRH receptor expression during the transdifferentiation process is finely and differentially regulated.
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Affiliation(s)
- Carlos Villalobos
- Dept. Fisiología y Bioquímica, Facultad de Medicina, Instituto de Biología y Genética Molecular, University of Valladolid, E-47005 Valladolid, Spain
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Targeted ablation of gonadotrophs in transgenic mice depresses prolactin but not growth hormone gene expression at birth as measured by quantitative mRNA detection. J Biomed Sci 2003. [DOI: 10.1007/bf02256333] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Nuñez L, Villalobos C, Senovilla L, García-Sancho J. Multifunctional cells of mouse anterior pituitary reveal a striking sexual dimorphism. J Physiol 2003; 549:835-43. [PMID: 12730343 PMCID: PMC2342984 DOI: 10.1113/jphysiol.2003.040758] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The existence of cells storing and secreting two different anterior pituitary (AP) hormones (polyhormonal cells) or responding to several hypothalamic releasing hormones (HRHs) (multiresponsive cells) has been reported previously. These multifunctional cells could be involved in paradoxical secretion (AP hormone secretion evoked by a non-corresponding HRH) and transdifferentiation (phenotypic switch between mature cell types without cell division). Despite their putative physiological relevance, a comprehensive characterization of multifunctional AP cells is lacking. Here we combine calcium imaging (to assess responses to the four HRHs) and multiple sequential immunoassay of the six AP hormones in the same individual cells to perform a complete phenotypic characterization of mouse AP cells. Polyhormonal and multiresponsive cells were identified within all five AP cell types. They were scarce in the more abundant cell types, somatotropes and lactotropes, but quite frequent in corticotropes and gonadotropes. Cells with mixed phenotypes were the rule rather than the exception in thyrotropes, where 56-83 % of the cells stored two to five different hormones. Multifunctional AP cells were much more abundant in females than in males, indicating that the hormonal changes associated with the sexual cycle may promote transdifferentiation. As the phenotypic analysis was performed here after stimulation with HRHs, the fraction of polyhormonal cells might have been underestimated. With this limitation, the polyhormonal cells detected here responded to the HRHs less than the monohormonal ones, suggesting that they might contribute less than expected a priori to paradoxical secretion. Overall, our results reveal a striking sexual dimorphism, the female pituitary being much more plastic than the male pituitary.
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Affiliation(s)
- Lucía Nuñez
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
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Abstract
The melanocortin (MC) gamma3-MSH is believed to signal through the MC3 receptor. We showed that it induces a sustained increase in intracellular free calcium levels ([Ca(2+)](i)) in a subpopulation of pituitary cells. Most of the cells responding to gamma3-MSH express more than one pituitary hormone mRNA. The effect of gamma3-MSH is blocked by SHU9119, a MC3R and MC4R antagonist, in only 50% of the responsive cells, suggesting that in half of these cells the mediating receptor is not the MC3R. Low picomolar doses of gamma3-MSH increase [Ca(2+)](i) in the growth hormone (GH)- and prolactin (PRL)-secreting GH3 cell line. gamma2-MSH and alpha-MSH display a similar effect. SHU9119 does not affect the gamma3-MSH-induced [Ca(2+)](i) response. MTII, a potent synthetic agonist of the MC3R, MC4R, and MC5R, also shows no or low potency in increasing [Ca(2+)](i). By means of RT-PCR, the mRNA of the MC2R, MC3R, and MC4R receptors is undetectable. Experiments testing gamma2-MSH analogues with single alanine replacements show that, unlike the classic MCRs, the His(5)-Phe(6)-Arg(7)-Trp(8) sequence in gamma2-MSH is not a core sequence for activating the gamma-MSH receptor in GH3 cells, whereas Met(3) is essential. Low nanomolar doses of gamma-MSH increase intracellular cAMP levels. Blockade of protein kinase A abolishes the [Ca(2+)](i) responses to gamma3-MSH. gamma2-MSH increases binding of [S(35)]GTPgammaS to membrane preparations of GH3 cells. The pharmacological characteristics of gamma-MSH peptides and analogues on [Ca(2+)](i) and the signal-transduction pathways present strong evidence for the expression of a hitherto uncharacterized gamma-MSH receptor in GH3 cells, belonging to the G protein-coupled receptor family.
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Affiliation(s)
- C Denef
- Laboratory of Cell Pharmacology, University of Leuven Medical School, B-3000 Leuven, Belgium.
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Abstract
Lactotropes in the pituitary gland might be useful models of how a cell type develops, differentiates, proliferates and regresses under the control of paracrine and autocrine signals. Lactotrope development during embryonic life is determined by a well-defined sequence of temporal and positional actions of locally produced members of the bone morphogenetic protein, hedgehog and fibroblast growth factor families. Transforming growth factor alpha (TGF-alpha), TGF-beta and galanin mediate the action of estrogen on the postnatal expansion of the lactotrope cell population and expression of the gene encoding prolactin in an autocrine/paracrine manner. Moreover, the classic hormone precursor pro-opiomelanocortin generates differentially glycosylated isoforms of its N-terminal fragment as paracrine controllers, which each induce distinct aspects of lactotrope differentiation and growth.
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Affiliation(s)
- Carl Denef
- Laboratory of Cell Pharmacology, University of Leuven (K.U. Leuven), Medical School, Campus Gasthuisberg (O&N), B-3000 Leuven, Belgium.
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