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Icyuz M, Zhang F, Fitch MP, Joyner MR, Challa AK, Sun LY. Physiological and metabolic characteristics of novel double-mutant female mice with targeted disruption of both growth hormone-releasing hormone and growth hormone receptor. Aging Cell 2021; 20:e13339. [PMID: 33755309 PMCID: PMC8045953 DOI: 10.1111/acel.13339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 12/27/2020] [Accepted: 01/12/2021] [Indexed: 12/19/2022] Open
Abstract
Mice with disruptions of growth hormone-releasing hormone (GHRH) or growth hormone receptor (GHR) exhibit similar phenotypes of prolonged lifespan and delayed age-related diseases. However, these two models respond differently to calorie restriction indicating that they might carry different and/or independent mechanisms for improved longevity and healthspan. In order to elucidate these mechanisms, we generated GHRH and GHR double-knockout mice (D-KO). In the present study, we focused specifically on the characteristics of female D-KO mice. The D-KO mice have reduced body weight and enhanced insulin sensitivity compared to wild-type (WT) controls. Growth retardation in D-KO mice is accompanied by decreased GH expression in pituitary, decreased circulating IGF-1, increased high-molecular-weight (HMW) adiponectin, and leptin hormones compared to WT controls. Generalized linear model-based regression analysis, which controls for body weight differences between D-KO and WT groups, shows that D-KO mice have decreased lean mass, bone mineral density, and bone mineral content, but increased adiposity. Indirect calorimetry markers including oxygen consumption, carbon dioxide production, and energy expenditure were significantly lower in D-KO mice relative to the controls. In comparison with WT mice, the D-KO mice displayed reduced respiratory exchange ratio (RER) values only during the light cycle, suggesting a circadian-related metabolic shift toward fat utilization. Interestingly, to date survival data suggest extended lifespan in D-KO female mice.
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Affiliation(s)
- Mert Icyuz
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
| | - Fang Zhang
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
| | - Michael P. Fitch
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
| | - Matthew R. Joyner
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
| | - Anil K. Challa
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
| | - Liou Y. Sun
- Department of Biology University of Alabama at Birmingham Birmingham Alabama USA
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Beckers A, Lodish MB, Trivellin G, Rostomyan L, Lee M, Faucz FR, Yuan B, Choong CS, Caberg JH, Verrua E, Naves LA, Cheetham TD, Young J, Lysy PA, Petrossians P, Cotterill A, Shah NS, Metzger D, Castermans E, Ambrosio MR, Villa C, Strebkova N, Mazerkina N, Gaillard S, Barra GB, Casulari LA, Neggers SJ, Salvatori R, Jaffrain-Rea ML, Zacharin M, Santamaria BL, Zacharieva S, Lim EM, Mantovani G, Zatelli MC, Collins MT, Bonneville JF, Quezado M, Chittiboina P, Oldfield EH, Bours V, Liu P, De Herder W, Pellegata N, Lupski JR, Daly AF, Stratakis CA. X-linked acrogigantism syndrome: clinical profile and therapeutic responses. Endocr Relat Cancer 2015; 22:353-67. [PMID: 25712922 PMCID: PMC4433400 DOI: 10.1530/erc-15-0038] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/23/2015] [Indexed: 12/31/2022]
Abstract
X-linked acrogigantism (X-LAG) is a new syndrome of pituitary gigantism, caused by microduplications on chromosome Xq26.3, encompassing the gene GPR101, which is highly upregulated in pituitary tumors. We conducted this study to explore the clinical, radiological, and hormonal phenotype and responses to therapy in patients with X-LAG syndrome. The study included 18 patients (13 sporadic) with X-LAG and microduplication of chromosome Xq26.3. All sporadic cases had unique duplications and the inheritance pattern in two families was dominant, with all Xq26.3 duplication carriers being affected. Patients began to grow rapidly as early as 2-3 months of age (median 12 months). At diagnosis (median delay 27 months), patients had a median height and weight standard deviation scores (SDS) of >+3.9 SDS. Apart from the increased overall body size, the children had acromegalic symptoms including acral enlargement and facial coarsening. More than a third of cases had increased appetite. Patients had marked hypersecretion of GH/IGF1 and usually prolactin, due to a pituitary macroadenoma or hyperplasia. Primary neurosurgical control was achieved with extensive anterior pituitary resection, but postoperative hypopituitarism was frequent. Control with somatostatin analogs was not readily achieved despite moderate to high levels of expression of somatostatin receptor subtype-2 in tumor tissue. Postoperative use of adjuvant pegvisomant resulted in control of IGF1 in all five cases where it was employed. X-LAG is a new infant-onset gigantism syndrome that has a severe clinical phenotype leading to challenging disease management.
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Affiliation(s)
- Albert Beckers
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Maya Beth Lodish
- Program on Developmental Endocrinology and Genetics, Section on Endocrinology & Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD
| | - Giampaolo Trivellin
- Program on Developmental Endocrinology and Genetics, Section on Endocrinology & Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD
| | - Liliya Rostomyan
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Misu Lee
- Helmholtz Zentrum München, Institute of Pathology, Neuherberg, Germany
| | - Fabio R Faucz
- Program on Developmental Endocrinology and Genetics, Section on Endocrinology & Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD
| | - Bo Yuan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Catherine S Choong
- Department of Pediatric Endocrinology & Diabetes, Princess Margaret Hospital for Children, Subiaco WA, Australia
| | - Jean-Hubert Caberg
- Department of Clinical Genetics, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Elisa Verrua
- Endocrinology and Diabetology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | | | - Tim D Cheetham
- Department of Paediatric Endocrinology, Royal Victoria Infirmary, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jacques Young
- INSERM U 693, GHU Paris-Sud - Hôpital de Bicêtre, 78 rue du Général Leclerc, 94270 Le Kremlin-Bicêtre, France
| | - Philippe A Lysy
- Pediatric Endocrinology Unit, Université Catholique de Louvain, Bruxelles, Belgium
| | - Patrick Petrossians
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Andrew Cotterill
- Mater Medical Research Institute, University of Queensland, Brisbane, Queensland, Australia
| | | | - Daniel Metzger
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Emilie Castermans
- Department of Clinical Genetics, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Maria Rosaria Ambrosio
- Department of Medical Sciences, Section of Endocrinology, University of Ferrara, Ferrara, Italy
| | - Chiara Villa
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
- Service d’Anatomie et Cytologie Pathologiques, Hopital Foch, Suresnes, France
- INSERM Unité 1016, Institut Cochin, Hopital Cochin, Université Paris Descartes, Paris, France
| | - Natalia Strebkova
- Endocrinological Research Centre, Institute of Pediatric Endocrinology, Moscow, Russia
| | - Nadia Mazerkina
- Service d’Anatomie et Cytologie Pathologiques, Hopital Foch, Suresnes, France
- Burdenko Neurosurgery Institute, Moscow, Russia
| | | | | | | | - Sebastian J. Neggers
- Department of Medicine, Section of Endocrinology, Erasmus University Medical Center Rotterdam / Pituitary Center Rotterdam, Rotterdam, The Netherlands
| | - Roberto Salvatori
- Department of Endocrinology, Johns Hopkins University, Baltimore, Maryland, United States
| | - Marie-Lise Jaffrain-Rea
- Department of Endocrinology, University of L’Aquila, IRCCS, L’Aquila, and Neuromed, Pozilli, Italy
| | - Margaret Zacharin
- Department of Endocrinology and Diabetes The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | | | - Sabina Zacharieva
- Clinical Center of Endocrinology and Gerontology, Medical University of Sofia, Sofia, Bulgaria
| | - Ee Mun Lim
- Department of Clinical Biochemistry, Pharmacology & Toxicology, PathWest QEII-Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Giovanna Mantovani
- Endocrinology and Diabetology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Maria Chaira Zatelli
- Department of Medical Sciences, Section of Endocrinology, University of Ferrara, Ferrara, Italy
| | - Michael T Collins
- Skeletal Clinical Studies Unit, National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, USA
| | - Jean-François Bonneville
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Martha Quezado
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (NIH), Bethesda, Maryland, 20892, USA
| | - Prashant Chittiboina
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
| | - Edward H. Oldfield
- Department of Neurosurgery, University of Virginia Medical School, Charlottesville, Virginia, USA
| | - Vincent Bours
- Department of Clinical Genetics, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Wouter De Herder
- Department of Medicine, Section of Endocrinology, Erasmus University Medical Center Rotterdam / Pituitary Center Rotterdam, Rotterdam, The Netherlands
| | - Natalia Pellegata
- Helmholtz Zentrum München, Institute of Pathology, Neuherberg, Germany
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
- Department of Pediatrics, and Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
- Texas Children’s Hospital, Houston, Texas, USA
| | - Adrian F. Daly
- Department of Endocrinology, Centre Hospitalier Universitaire de Liège, University of Liège, Liège, Belgium
| | - Constantine A. Stratakis
- Program on Developmental Endocrinology and Genetics, Section on Endocrinology & Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD
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Huang YH, Sun MJ, Jiang M, Fu BY. Immunohistochemical localization of glucagon and pancreatic polypeptide on rat endocrine pancreas: coexistence in rat islet cells. Eur J Histochem 2009; 53:e10. [PMID: 30256861 PMCID: PMC3167281 DOI: 10.4081/ejh.2009.e10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2009] [Indexed: 11/22/2022] Open
Abstract
We used immunofluorescence double staining method to investigate the cellular localization of glucagon and pancreatic polypeptide (PP) in rat pancreatic islets. The results showed that both A-cells (glucagon-secreting cells) and PP-cells (PP-secreting cells) were located in the periphery of the islets. However, A-cells and PP-cells had a different regional distribution. Most of A-cells were located in the splenic lobe but a few of them were in the duodenal lobe of the pancreas. In contrast, the majority of PP-cells were found in the duodenal lobe and a few of them were in the splenic lobe of the pancreas. Furthermore, we found that 67.74% A-cells had PP immunoreactivity, 70.92% PP-cells contained glucagon immunoreactivity with immunofluorescence double staining. Our data support the concept of a common precursor stem cell for pancreatic hormone-producing cells.
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Affiliation(s)
- Y H Huang
- Department of Gastroenterology, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - M J Sun
- Department of Gastroenterology, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - M Jiang
- Department of Gastroenterology, The First Affiliated Hospital, China Medical University, Shenyang, China
| | - B Y Fu
- Department of Gastroenterology, The First Affiliated Hospital, China Medical University, Shenyang, China
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Fainstein Day P, Frohman L, Garcia Rivello H, Reubi JC, Sevlever G, Glerean M, Fernandez Gianotti T, Pietrani M, Rabadan A, Racioppi S, Bidlingmaier M. Ectopic growth hormone-releasing hormone secretion by a metastatic bronchial carcinoid tumor: a case with a non hypophysial intracranial tumor that shrank during long acting octreotide treatment. Pituitary 2007; 10:311-9. [PMID: 17373589 DOI: 10.1007/s11102-007-0019-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ectopic acromegaly represents less than 1% of the reported cases of acromegaly. Although clinical improvement is common after treatment with somatostatin (SMS) analogs, the biochemical response and tumor size of the growth hormone-releasing hormone (GHRH)-producing tumor and its metastases are less predictable. Subject A 36-year-old male was referred because of a 3-year history of acromegaly related symptoms. He had undergone lung surgery in 1987 for a "benign" carcinoid tumor. Endocrine evaluation confirmed acromegaly Plasma IGF-1: 984 ng/ml (63-380), GH: 49.8 ng/ml (<5). MRI showed a large mass in the left cerebellopontine angle and diffuse pituitary hyperplasia. Pulmonary, liver and bone metastases were shown by chest and abdominal CT scans. Ectopic GHRH secretion was suspected. Methods Measurement of circulating GHRH levels by fluorescence immunoassay levels and immunohistochemical study of the primary lung tumor and metastatic tissue with anti-GHRH and anti-somatostatin receptor type 2 (sst2A) antibodies. Results Basal plasma GHRH: 4654 pg/ml (<100). Pathological study of liver and bone biopsy material and lung tissue removed 19 years earlier was consistent with an atypical carcinoid producing GHRH and exhibiting sst2A receptor expression. Treatment with octreotide LAR 20-40 mg q. month resulted in normalization of plasma IGF-1 levels. Circulating GHRH levels decreased dramatically. The size of the left prepontine cistern mass, with SMS receptors shown by a radiolabeled pentetreotide scan, decreased by 80% after 18 months of therapy. Total regression of pituitary enlargement was also observed. No changes were observed in lung and liver metastases. After 24 months of therapy the patient is asymptomatic and living a full and active life.
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Affiliation(s)
- Patricia Fainstein Day
- Department of Endocrinology and Nuclear Medicine, Hospital Italiano, Gascón 450 (1187), Buenos Aires, Argentina.
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5
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Huang YH, Ito A, Arai R. Immunohistochemical localization of monoamine oxidase type B in pancreatic islets of the rat. J Histochem Cytochem 2005; 53:1149-58. [PMID: 15923360 DOI: 10.1369/jhc.5a6658.2005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Monoamine oxidase (MAO) is regarded as a mitochondrial enzyme. This enzyme localizes on the outer membrane of mitochondria. There are two kinds of MAO isozymes, MAO type A (MAOA) and type B (MAOB). Previous studies have shown that MAOB activity is found in the pancreatic islets. This activity in the islets is increased by the fasting-induced decrease of plasma glucose level. Islet B cells contain monoamines in their secretory granules. These monoamines inhibit the secretion of insulin from the B cells. MAOB is active in degrading monoamines. Therefore, MAOB may influence the insulin-secretory process by regulating the stores of monoamines in the B cells. However, it has not been determined whether MAOB is localized on B cells or other cell types of the islets. In the present study, we used both double-labeling immunofluorescence histochemical and electron microscopic immunohistochemical methods to examine the subcellular localization of MAOB in rat pancreatic islets. MAOB was found in the mitochondrial outer membranes of glucagon-secreting cells (A cells), insulin-secreting cells (B cells), and some pancreatic polypeptide (PP)-secreting cells (PP cells), but no MAOB was found in somatostatin-secreting cells (D cells), nor in certain other PP cells. There were two kinds of mitochondria in pancreatic islet B cells: one contains MAOB on their outer membranes, but a substantial proportion of them lack this enzyme. Our findings indicate that pancreatic islet B cells contain MAOB on their mitochondrial outer membranes, and this enzyme may be involved in the regulation of monoamine levels and insulin secretion in the B cells.
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Affiliation(s)
- Yu-Hong Huang
- Department of Anatomy, Shiga University of Medical Science, Otsu, Shiga 520-2192, Japan
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Jirawatnotai S, Aziyu A, Osmundson EC, Moons DS, Zou X, Kineman RD, Kiyokawa H. Cdk4 is indispensable for postnatal proliferation of the anterior pituitary. J Biol Chem 2004; 279:51100-6. [PMID: 15456744 DOI: 10.1074/jbc.m409080200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For proper development and tissue homeostasis, cell cycle progression is controlled by multilayered mechanisms. Recent studies using knock-out mice have shown that animals can develop relatively normally with deficiency for each of the G1/S-regulatory proteins, D-type and E-type cyclins, cyclin-dependent kinase 4 (Cdk4), and Cdk2. Although Cdk4-null mice show no embryonic lethality, they exhibit specific endocrine phenotypes, i.e. dwarfism, infertility, and diabetes. Here we have demonstrated that Cdk4 plays an essential non-redundant role in postnatal proliferation of the anterior pituitary. Pituitaries from wild-type and Cdk4-null embryos at embryonic day 17.5 are morphologically indistinguishable with similar numbers of cells expressing a proliferating marker, Ki67, and cells expressing a differentiation marker, growth hormone. In contrast, anterior pituitaries of Cdk4-null mice at postnatal 8 weeks are extremely hypoplastic with markedly decreased numbers of Ki67+ cells, suggesting impaired cell proliferation. Pituitary hyperplasia induced by transgenic expression of human growth hormone-releasing hormone (GHRH) is significantly diminished in the Cdk4+/- genetic background and completely abrogated in the Cdk4-/- background. Small interfering RNA (siRNA)-mediated knockdown of Cdk4 inhibits GHRH-induced proliferation of GH3 somato/lactotroph cells with restored expression of GHRH receptors. Cdk4 siRNA also inhibits estrogen-dependent cell proliferation in GH3 cells and closely related GH4 cells. In contrast, Cdk6 siRNA does not diminish proliferation of these cells. Furthermore, Cdk4 siRNA does not affect GHRH-induced proliferation of mouse embryonic fibroblasts or estrogen-dependent proliferation of mammary carcinoma MCF-7 cells. Taken together, Cdk4 is dispensable for prenatal development of the pituitary or proliferation of other non-endocrine tissues but indispensable specifically for postnatal proliferation of somato/lactotrophs.
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Affiliation(s)
- Siwanon Jirawatnotai
- Department of Biochemistry, University of Illinois College of Medicine, Chicago, Illinois 60607, USA
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Acromegaly Secondary to Ectopic Growth Hormone-Releasing Hormone-Secreting Bronchial Carcinoid Cured After Pneumectomy. ACTA ACUST UNITED AC 2003. [DOI: 10.1097/01.ten.0000089860.69958.83] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Frohman LA, Kineman RD. Growth hormone-releasing hormone and pituitary development, hyperplasia and tumorigenesis. Trends Endocrinol Metab 2002; 13:299-303. [PMID: 12163232 DOI: 10.1016/s1043-2760(02)00613-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Growth hormone-releasing hormone (GHRH) is essential for expansion of the somatotrope lineage during pituitary development, and excessive GHRH secretion and/or action results in unregulated somatotrope proliferation and neoplastic transformation. Our understanding of the molecular and morphological bases for these effects from both animal and clinical studies has greatly increased during the past decade. However, many features of the cellular pathways remain to be defined, including the interaction of other genes in the multistep process of somatotrope tumorigenesis.
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Affiliation(s)
- Lawrence A Frohman
- Section of Endocrinology, Dept of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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9
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Kineman RD, Teixeira LT, Amargo GV, Coschigano KT, Kopchick JJ, Frohman LA. The effect of GHRH on somatotrope hyperplasia and tumor formation in the presence and absence of GH signaling. Endocrinology 2001; 142:3764-73. [PMID: 11517152 DOI: 10.1210/endo.142.9.8382] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Excessive GHRH stimulation leads to somatotrope hyperplasia and, ultimately, pituitary adenoma formation in the metallothionein promoter-driven human GHRH (hGHRH) transgenic mouse. This pituitary phenotype is similar to that observed in humans with ectopic production of GHRH. In both mice and man, GHRH hyperstimulation also results in dramatic increases in circulating GH and IGF-I. To determine whether GH/IGF-I modulates the development and growth rate of GHRH-induced pituitary tumors, pituitary growth and histology were evaluated in mice generated from cross-breeding metallothionein promoter-driven hGHRH transgenic mice with GH receptor binding protein (GHR) gene disrupted mice (GHR(-/-)). Expression of the hGHRH transgene in 2-month-old GHR intact (GHR(+)) mice resulted in the doubling of pituitary weight that was largely attributed to an increase in the number of GH-immunopositive cells. Pituitary weight of GHR(+) hGHRH mice did not significantly change between 2 and 6 months of age, whereas at 12 months, weights increased up to 100-fold those of GHR(+) pituitaries, and 70% of the glands contained grossly visible adenomas. All adenomas stained positively for GH, whereas some showed scattered PRL staining. Pituitaries of GHR(-/-) mice were half the size of those of GHR(+) mice. Although reduced in size, the histological features of GHR(-/-) mouse pituitaries were suggestive of somatotrope hyperplasia. Despite evidence of somatotrope hyperplasia, pituitaries from GHR(-/-) mice as old as 28 months of age were similar in size to those of 2-month-old mice and did not show signs of adenoma formation. Expression of the hGHRH transgene in GHR(-/-) mice did not significantly increase pituitary size between 2 and 6 months of age. However, at 12 months the majority of GHR(-/-), hGHRH pituitaries developed adenomas with mean pituitary weight and histological features similar to those of GHR(+), hGHRH mice. These observations demonstrate that intact GH signaling is not required for GHRH tumor formation. Although the majority of GHR(+), hGHRH and GHR(-/-), hGHRH pituitaries developed tumors by 12 months of age, a small subset remained morphologically indistinct from those at 2 months of age. These observations taken together with the fact that overt tumor formation is preceded by a static pituitary growth phase between 2 and 6 months, indicates that protective mechanisms are in place to maintain pituitary mass despite hGHRH hyperstimulation.
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Affiliation(s)
- R D Kineman
- Department of Medicine, University of Illinois, Chicago, Illinois 60612, USA.
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10
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Peng XD, Park S, Gadelha MR, Coschigano KT, Kopchick JJ, Frohman LA, Kineman RD. The growth hormone (GH)-axis of GH receptor/binding protein gene-disrupted and metallothionein-human GH-releasing hormone transgenic mice: hypothalamic neuropeptide and pituitary receptor expression in the absence and presence of GH feedback. Endocrinology 2001; 142:1117-23. [PMID: 11181526 DOI: 10.1210/endo.142.3.8005] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Elevation of circulating GH acts to feed back at the level of the hypothalamus to decrease GH-releasing hormone (GHRH) and increase somatostatin (SRIF) production. In the rat, GH-induced changes in GHRH and SRIF expression are associated with changes in pituitary GHRH receptor (GHRH-R), GH secretagogue receptor (GHS-R), and SRIF receptor subtype messenger RNA (mRNA) levels. These observations suggest that GH regulates its own synthesis and release not only by altering expression of key hypothalamic neuropeptides but also by modulating the sensitivity of the pituitary to hypothalamic input, by regulating pituitary receptor synthesis. To further explore this possibility, we examined the relationship between the expression of hypothalamic neuropeptides [GHRH, SRIF, and neuropeptide Y (NPY)] and pituitary receptors [GHRH-R, GHS-R, and SRIF receptor subtypes (sst2 and sst5)] in two mouse strains with alterations in the GH-axis; the GH receptor/binding protein gene-disrupted mouse (GHR/BP-/-) and the metallothionein promoter driven human GHRH (MT-hGHRH) transgenic mouse. In GHR/BP-/- mice, serum insulin-like growth factor I levels are low, and circulating GH is elevated because of the lack of GH negative feedback. Hypothalamic GHRH mRNA levels in GHR/BP-/- mice were 232 +/- 20% of GHR/BP+/+ littermates (P < 0.01), whereas SRIF and NPY mRNA levels were reduced to 86 +/- 2% and 52 +/- 3% of controls, respectively (P < 0.05; ribonuclease protection assay). Pituitary GHRH-R and GHS-R mRNA levels of GHR/BP-/- mice were elevated to 275 +/- 55% and 319 +/- 68% of GHR/BP+/+ values (P < 0.05, respectively), whereas the sst2 and sst5 mRNA levels did not differ from GHR/BP intact controls as determined by multiplex RT-PCR. Therefore, in the absence of GH negative feedback, both hypothalamic and pituitary expression is altered to favor stimulation of GH synthesis and release. In MT-hGHRH mice, ectopic hGHRH transgene expression elevates circulating GH and insulin-like growth factor I. In this model of GH excess, endogenous (mouse) hypothalamic GHRH mRNA levels were reduced to 69 +/- 6% of nontransgenic controls, whereas SRIF mRNA levels were increased to 128 +/- 6% (P < 0.01). NPY mRNA levels were not significantly affected by hGHRH transgene expression. Also, MT-hGHRH pituitary GHRH-R and GHS-R mRNA levels did not differ from controls. However, sst2 and sst5 mRNA levels in MT-hGHRH mice were increased to 147 +/- 18% and 143 +/- 16% of normal values, respectively (P < 0.05). Therefore, in the presence of GH negative feedback, both hypothalamic and pituitary expression is altered to favor suppression of GH synthesis and release.
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Affiliation(s)
- X D Peng
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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11
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Arvat E, Gianotti L, Giordano R, Broglio F, Maccario M, Lanfranco F, Muccioli G, Papotti M, Graziani A, Ghigo E, Deghenghi R. Growth hormone-releasing hormone and growth hormone secretagogue-receptor ligands: focus on reproductive system. Endocrine 2001; 14:35-43. [PMID: 11322500 DOI: 10.1385/endo:14:1:035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Growth hormone-releasing hormone (GHRH) and somatostatin are the most important hypothalamic neurohormones controlling growth hormone (GH) secretion. Several neurotransmitters and neuropeptides also play an important role in the control of GH secretion, mainly acting via modulation of GHRH and somatostatin. In the past two decades, particular attention has been given to a new family of substances showing a strong GH-releasing effect: GH secretagogues (GHSs). GHSs increase GH secretion in a dose- and age-related manner after iv and even oral administration. The endocrine effects of GHSs, are not fully specific for GH; they show, in fact, prolactin- (PRL), adenocorticotropic hormone- and cortisol-releasing effects. Specific GHS receptors are present in both the central nervous system and peripheral tissues, where they mediate several extraendocrine effects of GHSs. The isolation of these "orphan" receptors suggested the existence of an endogenous GHS-like ligand that could be represented by a recently discovered gastric peptide, named ghrelin. The interaction between GHSs and GHRH at the central level and in the pituitary gland, but not at peripheral level, has clearly been shown. Because GHRH and GHS receptors share the same localization in some peripheral tissues, they may have some interactions even at this level.
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Affiliation(s)
- E Arvat
- Department of Internal Medicine, University of Turin, Italy
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12
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Teixeira LT, Kiyokawa H, Peng XD, Christov KT, Frohman LA, Kineman RD. p27Kip1-deficient mice exhibit accelerated growth hormone-releasing hormone (GHRH)-induced somatotrope proliferation and adenoma formation. Oncogene 2000; 19:1875-84. [PMID: 10773877 DOI: 10.1038/sj.onc.1203490] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
p27Kip1 (p27) controls cell cycle progression by binding to and inhibiting the activity of cyclin dependent kinases. Disruption of the p27 gene in mice (p27-/-) results in increased body growth with a disproportionate enlargement of the spleen, thymus, testis, ovary and pituitary. The increase in pituitary size is due to selective hyperplasia of the intermediate lobe (IL) while the anterior lobe (AL) is not overtly affected. p27 heterozygous mice (p27+/-), as well as p27-/- mice, are hypersensitive to radiation- and chemical-induced tumors compared to wildtype (p27+/+) littermates. Therefore, unlike classical tumor suppressors, only a reduction in p27 levels is necessary to predispose tissues to secondary tumor promoters. Consistent with these studies is the fact that the p27 gene sequence and mRNA levels appear normal in human pituitary adenomas while p27 protein levels are decreased. Therefore, a reduction in p27 levels could be sufficient to sensitize pituitary cells to tumorigenic factors. To test this hypothesis, metallothionein promoter-driven, human growth hormone-releasing hormone (MT-hGHRH) transgenic mice, that exhibit somatotrope hyperplasia before 9 months of age and subsequent adenoma formation with 30 - 40% penetrance, were crossbred with p27+/- mice for two successive generations to produce p27+/+, p27+/- and p27-/- mice that expressed the hGHRH transgene. At 10 - 12 weeks of age, p27-/- and p27+/+, hGHRH mice were larger than their p27+/+ littermates and displayed characteristic hyperplasia of the IL and AL, respectively. Expression of the hGHRH transgene in both p27+/- and p27-/- mice selectively expanded the population of somatotropes within the AL, where pituitaries of p27+/-, hGHRH and p27-/-, hGHRH mice were two- and fivefold larger than p27+/+, hGHRH pituitaries, respectively. There was also a synergistic effect of hGHRH transgene expression and p27-deficiency on liver, spleen and ovarian growth. At 6 - 8 months of age, 83% of p27+/-, hGHRH mice displayed macroscopic AL adenomas (>100 mg), while all pituitaries from p27+/+, hGHRH mice remained hyperplastic (<20 mg). In contrast to the dramatic effects of p27-deficiency on hGHRH-induced organ growth, elimination of p53, by crossbreeding MT-hGHRH mice to p53-deficient mice, did not augment the hyperplastic/tumorigenic effects of hGHRH transgene expression. Taken together these results demonstrate that a reduction in p27 expression is sufficient to sensitize somatotropes to the proliferative actions of excess GHRH, resulting in the earlier appearance and increased penetrance of hGHRH-induced pituitary tumors.
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Affiliation(s)
- L T Teixeira
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA
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13
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Kovacs M, Kineman RD, Schally AV, Zarandi M, Groot K, Frohman LA. Effects of antagonists of growth hormone-releasing hormone (GHRH) on GH and insulin-like growth factor I levels in transgenic mice overexpressing the human GHRH gene, an animal model of acromegaly. Endocrinology 1997; 138:4536-42. [PMID: 9348175 DOI: 10.1210/endo.138.11.5498] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transgenic mice overexpressing the human GH-releasing hormone (hGHRH) gene, an animal model of acromegaly, were used to investigate the effects of potent GHRH antagonists MZ-4-71 and MZ-5-156 on the excessive GH and insulin-like growth factor I (IGF-I) secretion caused by overproduction of hGHRH. Because metallothionein (MT)-GHRH mice express the hGHRH transgene in various tissues, including the pituitary and hypothalamus, initial experiments focused on the effectiveness of the GHRH antagonists in blocking basal and stimulated GH secretion from pituitary cells in vitro. Both MZ-4-71 and MZ-5-156 suppressed basal release of GH from superfused MT-GHRH pituitary cells, apparently by blocking the action of endogenously produced hGHRH. In addition, these antagonists effectively eliminated the response to stimulatory action of exogenous hGHRH(1-29)NH2 (30 and 100 nM). To ascertain whether MZ-4-71 and MZ-5-156 could antagonize the effect of hGHRH hyperstimulation in vivo, each antagonist was administered to MT-GHRH transgenic mice in a single iv dose of 10-200 microg. Both compounds decreased serum GH levels in transgenic mice by 39-72% at 1 h after injection. The inhibitory effect of 50 microg MZ-5-156 was maintained for 5 h. Twice daily ip administration of 100 microg MZ-5-156 for 3 days suppressed the highly elevated serum GH and IGF-I concentrations in transgenic mice by 56.8% and 39.0%, respectively. This treatment also reduced IGF-I messenger RNA levels in the liver by 21.8% but did not affect the level of GH messenger RNA in the pituitary. Our results demonstrate that GHRH antagonists MZ-4-71 and MZ-5-156 can inhibit elevated GH levels caused by overproduction of hGHRH. The suppression of circulating GH concentrations induced by the antagonists seems to be physiologically relevant, because both IGF-I secretion and synthesis also were reduced. Our findings, showing the suppression of GH and IGF-I secretion with GHRH antagonists, suggest that this class of analogs could be used for the diagnosis and therapy of disorders characterized by excessive GHRH secretion.
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Affiliation(s)
- M Kovacs
- Department of Medicine, Tulane University School of Medicine, New Orleans, Louisiana 70146, USA
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14
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Stefaneanu L, Kovacs K. Transgenic models of pituitary diseases. Microsc Res Tech 1997; 39:194-204. [PMID: 9361270 DOI: 10.1002/(sici)1097-0029(19971015)39:2<194::aid-jemt10>3.0.co;2-m] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Transgenic mice are valuable experimental models of human endocrine diseases. Targeted ablation of specific cell lineages or insertion of genes coding for releasing factors, hormones, growth factors, and oncogenes fused with appropriate promoters, or mutated genes, can induce several pituitary disorders. Various hyposecretory and hypersecretory states have been induced, some of them due to functioning pituitary adenomas. Adenohypophysial changes in such disorders have been thoroughly investigated in many of the transgenic lines. Functioning and silent pituitary adenomas resemble those seen in human patients, and are invaluable models of tumorigenesis. The available models have not been sufficiently exploited and new models are expected in the near future. In this review, the morphologic changes of the pituitary are described in transgenic mice and, when available, the ultrastructural alterations are included.
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Affiliation(s)
- L Stefaneanu
- Department of Pathology, St. Michael's Hospital, University of Toronto, Ontario, Canada
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15
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Gnessi L, Fabbri A, Spera G. Gonadal peptides as mediators of development and functional control of the testis: an integrated system with hormones and local environment. Endocr Rev 1997; 18:541-609. [PMID: 9267764 DOI: 10.1210/edrv.18.4.0310] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- L Gnessi
- Dipartimento di Fisiopatologia Medica, Università di Roma La Sapienza, Italy
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16
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Abstract
Growth hormone (GH) secretion is under the control of the hypothalamic hormones GH-releasing hormone (GHRH) and somatostatin (SRIF), and is regulated by feedback effects of GH and insulin-like growth factor (IGF-1). GHRH and SRIF act on somatotropes by binding to G-protein-coupled receptors. GHRH activates the stimulatory G protein (Gs), leading primarily to activation of adenylyl cyclase and protein kinase A. SRIF activates the inhibitory G protein (Gi). Several animal models enable the study of various disorders of GH secretion in vivo. Genetic models of impaired GH secretion include the little (lit) mouse, the dwarf (dw) rat, the fatty (fa) rat, and the high-growth (hg) mouse. Transgenic models of impaired and excessive GH secretion, respectively, include the tyrosine hydroxylase-human GH (TH-hGH) transgenic mouse and the metallothionein-human GHRH transgenic mouse. These models encompass a wide spectrum of disorders of GH secretion, involving defects of hypothalamic regulation, feedback control at the pituitary level, or the mechanism of GHRH action in the somatotrope. They may provide insights into our understanding of human GH secretory disorders.
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Affiliation(s)
- L A Frohman
- Department of Medicine, University of Illinois at Chicago 60612, USA
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17
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Briand P, Kahn A, Vandewalle A. Targeted oncogenesis: A powerful method to derive renal cell lines. Kidney Int 1995; 47:388-94. [PMID: 7723228 DOI: 10.1038/ki.1995.51] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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18
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Abstract
This chapter has presented a somewhat complex view of the gonadotrope population, indicating that it consists of independent subsets. There may be regulatory cells that influence development and other ancillary processes needed for normal reproduction. For example, normal differentiation of PRL cells requires a functioning population of gonadotropes (Kendall et al., 1991). In addition, gonadotropes appear to be autoregulatory; subsets may produce inhibin or activin (in rats) and follistatin. Production of GnRH itself may serve as another regulatory tool. The gonadotrope population appears to be quite dynamic and convertible in the female rat. Cytological and cytochemical changes with the stage of the cycle are obvious. Increases in the numbers of immunoreactive gonadotropes parallel increases in GnRH target cells and culminate in peak expression of LH and FSH beta subunit mRNAs. The immunoreactive gonadotropes are greatly reduced after the surge activity, as though the cells had disappeared from the population. However, gonadotropes can still be detected by their content of gonadotropin mRNAs. This finding has led to the hypothesis that the gonadotropes recycle themselves. However, do they go through a resting phase? Is there a normal cycle of cell death and turnover? These are basic questions that must be answered in order to understand how the population is organized and renewed. Finally, we have returned to one of our original problems. Whereas it is clear that nonparallel release can be brought about by granules or cells with only one gonadotropin, the exact mechanisms that sort the gonadotropin molecules or turn off bihormonal expression are not known. A combination of autoregulatory events involving follistatin, activin, inhibin, and possibly steroids may play a role in modulating expression by a given subset. Delays in maturation may also prevent secretion of FSH and, hence, effect the delayed rise seen during late proestrus. The nonsecretory FSH cells seen in the studies by Lloyd and Childs (1988a) may be delayed maturers, requiring additional receptor types or changes in the calcium flux pattern to secrete their product. We also have a new question to address. What is the significance of the presence of GH in proestrous gonadotropes? Is GH a regulatory hormone, bound to receptors inside gonadotropes, or do subsets of somatotropes augment the population, producing a cocktail of GH and gonadotropins to aid ovulation? Either hypothesis is intriguing. Co-storage of GH and gonadotropins would be an efficient way of providing the hormones needed by the ovary. However, further work with in situ hybridization is needed to detect GH mRNA in such cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- G V Childs
- Department of Anatomy and Neurosciences, University of Texas Medical Branch, Galveston 77555
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19
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Mayo KE, Godfrey PA, Suhr ST, Kulik DJ, Rahal JO. Growth hormone-releasing hormone: synthesis and signaling. RECENT PROGRESS IN HORMONE RESEARCH 1995; 50:35-73. [PMID: 7740167 DOI: 10.1016/b978-0-12-571150-0.50007-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The molecular characterization of GHRH and the GHRH receptor provides a framework for understanding the hypothalamic regulation of pituitary somatotroph function. The signaling events discerned from our investigation of GHRH receptor structure and function form the basis of a model for GHRH action, which is shown in Fig. 20. GHRH interaction with its seven transmembrane domain Gs-coupled receptor on the somatotroph (step 1) leads to the release of growth hormone from secretory granules (step 2), which is likely to involve a G protein-mediated interaction with ion channels, and to a stimulation of intracellular cAMP accumulation (step 3) (Mayo, 1992; Lin et al., 1992; Gaylinn et al., 1993). In several cell types tested, elevated cAMP leads to the phosphorylation and activation of the transcription factor CREB by protein kinase A (Gonzalez and Montminy, 1989; Sheng et al., 1991), and one target gene for CREB action is the pituitary-specific transcription factor Pit-1 or GHF-1 (step 4) (Bodner et al., 1988; Ingraham et al., 1988; McCormick et al., 1990). Pit-1 is a prototypic POU domain protein that is required for the appropriate regulation of the growth hormone gene in somatotroph cells, thus providing a pathway by which a GHRH signal can lead to increased growth hormone synthesis in the pituitary (step 5). In addition, Pit-1 is likely to directly regulate the synthesis of the GHRH receptor (step 6), in that the receptor is not expressed in the pituitary of dw/dw mice that lack functional Pit-1 (Lin et al., 1992), and a cotransfected Pit-1 expression construct can activate the GHRH receptor promoter in transiently transfected CV1 cells (Lin et al., 1993). It remains to be determined whether additional direct regulation of the GHRH receptor gene in response to the cAMP signaling pathway occurs (step 7). The inhibitory peptide somatostatin presumably interacts with this same signaling pathway through G protein-mediated suppression of the cAMP pathway (Tallent and Reisine, 1992; Bell and Reisine, 1993). In agreement with the importance of this signaling system for normal growth, a transgene encoding a nonphosphorylatable mutant CREB protein, which blocks the function of the endogenous CREB protein, is able to cause somatotroph hypoplasia and dwarfism in mice when its expression is targeted to pituitary somatotrophs (Struthers et al., 1991). Several steps in the signaling pathway leading to growth hormone secretion are subject to disruption, resulting in growth hormone deficiency.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K E Mayo
- Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208, USA
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20
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Lloyd RV, Jin L, Kulig E, Thiny MT, Fields K, Landefeld TD, Camper SA. Pit-1/ghf-1 transcription factor expression in rodent pituitaries. Endocr Pathol 1993; 4:146-154. [PMID: 32370429 DOI: 10.1007/bf02915303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The Pit-1/GHF-1 (Pit-1) transcription factor is important for the development of anterior pituitary cells that produce GH and PRL. We examined the expression of Pit-1 mRNA in pituitary tissues from rats and mice. Analysis of pituitaries from normal and GHRH transgenic mice showed that Pit-1 transcripts were readily detected in normal, hyperplastic, and neoplastic pituitaries. A cell line (GHRH-CL1) established from a GhRH transgenic mouse pituitary tumor in our laboratory also expressed Pit-1 mRNA. Normal rat pituitaries and those with estrogen-induced PRL cell hyperplasia expressed Pit-1 mRNA. There was a decrease in Pit-1 mRNA in hyperplastic rat pituitaries concomitant with a decrease In GH mRNA amounts and an increase in PRL mRNA amounts after estrogen treatment. Similarly, analysis of GH3 cells in vitro showed that estrogen and bFGF modulated PRL but not Pit-1 mRNA levels. Pit-1 mRNA was localized by combined in situ hybridization and immunohistochemistry to predominantly GH and PRL cells, although some TSH and LH cells in the rat pituitary also expressed Pit-1 mRNA, indicating wide distribution of the mRNA for this transcription factor in various anterior pituitary cell types. Analysis of cell proliferation in normal rat pituitary and GH3 cells revealed that estrogen and bFGF stimulated cell proliferation in normal pituitaries but inhibited proliferation in GH3 cells, whereas Pit-1 transcripts remained unchanged in both groups of cultured cells. These results indicate that Pit-1 mRNA is readily detected in normal, hyperplastic, and neoplastic rodent pituitaries. Changes in Pit-1 mRNA amounts appear to correlate more closely with changes in GH than PRL mRNA levels in cultured pituitary cells.Endocr Pathol 4:146-154, 1993.
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Affiliation(s)
- Ricardo V Lloyd
- Deparment of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Long Jin
- Deparment of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Elzbieta Kulig
- Deparment of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Michelle T Thiny
- Deparment of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Kristina Fields
- Deparment of Pathology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Thomas D Landefeld
- Pharmycology, University of Michigan Medical Center, Ann Arbor, Michigan
| | - Sally A Camper
- Human Genetics, University of Michigan Medical Center, Ann Arbor, Michigan
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Katz E, Ricciarelli E, Adashi EY. The potential relevance of growth hormone to female reproductive physiology and pathophysiology. Fertil Steril 1993; 59:8-34. [PMID: 8419227 DOI: 10.1016/s0015-0282(16)55610-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To assess possible interfacing between the somatotrophic and reproductive axes. DESIGN Literature review. MAIN OUTCOME MEASURES Ovarian growth hormone reception and action. RESULTS The available literature strongly supports a permissive role for the somatotrophic axis in the reproductive process. CONCLUSIONS Although a role for growth hormone in reproductive biology appears highly likely, its relevance to the process of puberty and to the normal workings of the menstrual cycle, as well as its possible application in reproductive pathology must await further investigation.
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Affiliation(s)
- E Katz
- Department of Obstetrics and Gynecology, University of Maryland School of Medicine, Baltimore 21201
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González-Crespo S, Boronat A. Expression of the rat growth hormone-releasing hormone gene in placenta is directed by an alternative promoter. Proc Natl Acad Sci U S A 1991; 88:8749-53. [PMID: 1924334 PMCID: PMC52587 DOI: 10.1073/pnas.88.19.8749] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Growth hormone-releasing hormone (GHRH) is a hypothalamic peptide that plays a critical role in controlling the synthesis and secretion of growth hormone by the anterior pituitary. GHRH has also been detected in other nonneural extrahypothalamic tissues, including rat placenta, although its role in the hormonal control of pregnancy and/or fetal development has not yet been defined. Here we present the isolation and characterization of cDNA clones corresponding to rat placental GHRH. The placental GHRH mRNA codes for a pre-pro-GHRH identical to that found in the hypothalamus, suggesting that the mature placental GHRH is identical to its hypothalamic counterpart. Nevertheless, the placental and the hypothalamic GHRH mRNAs differ in the region corresponding to the untranslated exon 1 because of the use of an alternative promoter in the placenta located 10 kilobases upstream from the hypothalamic promoter. A combined mechanism involving the use of tissue-specific alternative promoters and the differential splicing of exon 1 generates the mature GHRH transcript in placenta and hypothalamus. Multiple transcription initiation sites have been found in the placental GHRH mRNA, which correlates to the lack of a consensus TATA box in the promoter region.
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Affiliation(s)
- S González-Crespo
- Unidad de Bioquímica, Facultad de Farmacia, Universidad de Barcelona, Spain
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23
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Frohman LA, Downs TR, Chomczynski P, Frohman MA. Growth hormone-releasing hormone: structure, gene expression and molecular heterogeneity. ACTA PAEDIATRICA SCANDINAVICA. SUPPLEMENT 1990; 367:81-6. [PMID: 2220392 DOI: 10.1111/j.1651-2227.1990.tb11639.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- L A Frohman
- Department of Medicine, University of Cincinnati College of Medicine, Ohio
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