191 ESTROGEN REGULATES THE LOCALIZATION AND EXPRESSION OF CALBINDIN-D9k IN THE PITUITARY GLAND OF IMMATURE MALE RATS VIA THE ESTROGEN RECEPTOR ALPHA PATHWAY

2008 ◽  
Vol 20 (1) ◽  
pp. 175
Author(s):  
P. Tinnanooru ◽  
E.-B. Jeung
Keyword(s):  
Estrogen Receptor ◽  
Pituitary Gland ◽  
Estrogen Receptor Alpha ◽  
Anterior Lobe ◽  
Male Rats ◽  
Specific Cell ◽  
Intermediate Lobe ◽  
Immature Male ◽  
Calbindin D9k ◽  
Selective Ligand

Estrogen (E2; estradiol) plays a key role in the regulation of many pituitary hormones. It exerts its effects by binding to the intracellular estrogen receptor (ER), which then functions as a transcription factor. Although E2 has been shown to regulate calbindin-D9k (CaBP-9k) in the female reproductive system of rodents, the effects of E2 on the regulation of CaBP-9k in male rats remains to be elucidated. For investigation of E2-induced regulation of the pituitary CaBP-9k gene, immature male rats were injected with E2 daily for three consecutive days with a dose of 40 µg kg–1 body weight (BW). The expression levels of CaBP-9k mRNA and protein were analyzed by RT-PCR and Western blot analysis, respectively, in the absence and presence of ICI 182 780 (ICI), an E2 antagonist. In addition, the tissue localization of CaBP-9k was determined by immunohistochemistry. CaBP-9k was localized in the cytoplasm of a specific cell type (acidophils) in the anterior lobe of the pituitary gland and highly expressed in the intermediate lobe. Exposure to E2 increased the number of cells that stained positive for CaBP-9k. For determination of which ER subtype is involved in CaBP-9k regulation in the pituitary, the immature rats were treated with 1 mg kg–1 BW propyl pyrazole triol (PPT, an ER-α-selective ligand) or diarylpropionitrile (DPN, an ER-β-selective ligand) for three days. The data were analyzed by the non-parametric procedure of the Kruskal-Wallis test, followed by Dunnett's test for two-pair comparisons. Pituitary CaBP-9k expression was mainly mediated by PPT in immature male rats, whereas no significant alteration of pituitary CaBP-9k gene expression was observed after DPN treatment. In addition, the estrogenicity of PPT in the induction of CaBP-9k expression was completely blocked by an estrogen antagonist, ICI 182 780, indicating that pituitary CaBP-9k expression is solely induced by ER-α. Taken together, these results suggest that pituitary CaBP-9k is induced by estrogen in male rats and its expression is predominantly regulated by ER-α, but not ER-β.

Estrogen regulates the localization and expression of calbindin-D9k in the pituitary gland of immature male rats via the ERα-pathway

2008 ◽  
Vol 285 (1-2) ◽  
pp. 26-33 ◽  
Author(s):  
Pushpalatha Tinnanooru ◽  
Vu Hoang Dang ◽  
Thi Hoa Nguyen ◽  
Geun-Shik Lee ◽  
Kyung-Chul Choi ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Male Rats ◽  
Immature Male ◽  
Calbindin D9k

scholarly journals Immunocytochemical demonstration of tissue-type plasminogen activator in endocrine cells of the rat pituitary gland.

1985 ◽  
Vol 101 (1) ◽  
pp. 305-311 ◽  
Author(s):  
P Kristensen ◽  
L S Nielsen ◽  
J Grøndahl-Hansen ◽  
P B Andresen ◽  
L I Larsson ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Pituitary Gland ◽  
Endocrine Cells ◽  
Large Population ◽  
Cell Types ◽  
Anterior Lobe ◽  
Tissue Type ◽  
Intermediate Lobe ◽  
Posterior Lobe ◽  
Rat Pituitary

We immunocytochemically stained rat pituitary glands using antibodies against plasminogen activators of the tissue type (t-PA) and the urokinase type (u-PA). A large population of endocrine cells in the anterior lobe of the gland displayed intense cytoplasmic immunoreactivity with anti-t-PA. In some areas of the intermediate lobe we found a weak staining, and we observed weakly staining granular structures in the posterior lobe. Controls included absorption of the antibodies with highly purified t-PA. In addition, SDS PAGE followed by immunoblotting of pituitary gland extracts revealed only one band with an electrophoretic mobility similar to that of t-PA when stained with anti-t-PA IgG. No u-PA immunoreactivity was detected in the rat pituitary gland. Sequential staining experiments using antibodies against growth hormone and t-PA demonstrated that the t-PA-immunoreactive cells constitute a large subpopulation of the growth hormone-containing cells. These findings represent the first direct evidence for the presence of t-PA in cell types other than endothelial cells in the intact normal organism. In this article we discuss the implications of the results for a possible role of t-PA in the posttranslational processing of prohormones.

Bisphenol a regulates the estrogen receptor alpha signaling in developing hippocampus of male rats through estrogen receptor

Hippocampus ◽  
2014 ◽  
Vol 24 (12) ◽  
pp. 1570-1580 ◽  
Author(s):  
Xiao-Bin Xu ◽  
Ye He ◽  
Chen Song ◽  
Xin Ke ◽  
Shi-Jun Fan ◽  
...  
Keyword(s):  
Estrogen Receptor ◽  
Bisphenol A ◽  
Estrogen Receptor Alpha ◽  
Male Rats ◽  
Receptor Alpha

AUFTRETEN VON KASTRATIONSZELLEN IM HYPOPHYSENVORDERLAPPEN MÄNNLICHER RATTEN NACH BEHANDLUNG MIT EINEM ANTIANDROGEN

1966 ◽  
Vol 53 (1) ◽  
pp. 53-60 ◽  
Author(s):  
F. Neumann
Keyword(s):  
Pituitary Gland ◽  
Inhibitory Effect ◽  
Anterior Lobe ◽  
Male Rats ◽  
Hormone Deficiency ◽  
Pars Intermedia ◽  
Sexual Hormone ◽  
Releasing Factors

ABSTRACT Following the administration of an androgen-antagonist (1,2α-methylene-6-chloro-pregna-4,6-diene-17α-ol-3,20-dione = cyproterone) to male rats, changes are observed in the anterior lobe of the pituitary gland comparable to those which develop following removal of the gonads. The appearance of so called castration cells is very striking, particularly in the periphery, and in the area adjacent to the pars intermedia. The findings suggest that the androgen-antagonism of cyproterone also manifests itself in those receptors of the sex centre, which regulate the amount of gonadotrophin production and secretion in relation to the production of testosterone. Since endogenous testosterone can no longer exert its inhibitory effect on the sex centre, the sex centre, as in a state of sexual hormone deficiency, reacts by secreting releasing factors for gonadotrophins. Thus those cell elements in the anterior lobe of the pituitary gland are stimulated and this leads to the production of gonadotrophin.

scholarly journals Ultrastructural Changes of Melanotropic Cells of the Intermediate Share of the Adenogophysis in the Age Aspect

2021 ◽  
Vol 6 (1) ◽  
pp. 339-344
Author(s):  
A. Y. Chumachenko ◽  
◽  
A. G. Redka ◽  
Keyword(s):  
Pituitary Gland ◽  
Functional Activity ◽  
Secretory Granules ◽  
Male Rats ◽  
Ultrastructural Changes ◽  
Glandular Cell ◽  
Intermediate Lobe ◽  
Different Ages ◽  
Old Rats ◽  
Intact Rats

In modern theoretical and practical biology and medicine, the key problem of research is to reveal the patterns of structural and functional organization of the human and animal body at different stages of development. Literature sources provide very limited data on the organization of the intermediate lobe of the adenohypophysis in humans, leaving insufficiently studied the ultrastructural state and activity of melanotropic cells of the intermediate lobe of the adenohypophysis in animals of different ages, including rats. The issues of the intermediate pituitary gland functioning remain important and little studied, especially in the period of the beginning of the optic-thalamic system. The purpose of the research was to study the ultrastructural changes of melanotropic cells of the intermediate lobe of the adenohypophysis in rats of different ages in the norm. Material and methods. In accordance with the purpose of the study we conducted the experiment on 30 nonlinear white male rats of different ages: 14-, 45- and 90-day-old. The animals were kept in the vivarium in equivalent conditions. The keeping and using of animals was carried out in accordance with the provisions of the "General Ethical Principles of Animal Experiments", approved by the IV National Congress of Bioethics. While examining the intermediate pituitary gland of intact rats on the electron microscope, the material was fixed in 2.5% solution of glutaraldehyde on phosphate buffer with fixation in 1% solution of osmium tetroxide according to Caulfield. It was dehydrated in alcohols of increasing concentration (70%, 80%, 90%, 100%) and acetone, poured into a mixture of epon-araldite. Semi-thin sections were made from the obtained blocks, which were stained with toluidine blue. Results and discussion. At the ultrastructural level in the intermediate lobe of the adenohypophysis of 14-day-old intact rats, several cell types could be identified that differed in the number and size of secretory granules. The ultrastructure of glandular cells of 45-day-old rats had no significant differences compared with 14-day-old animals. Secretory granules of different sizes and electron densities were observed in the cytoplasm of melanotropic cells. It was often possible to see a glandular cell with numerous secretory granules in one part of the cytoplasm, while in another they were virtually absent. Most melanotropocytes were characterized by slightly compacted mitochondria, but their numbers were slightly higher than in 45-day-old rats. The nuclei of most cells were large, oval in shape with a clear structure of nucleoli and their ribosomal component. The latter represented groups of ribosomes that were collected in osmophilic complexes. The amount of heterochromatin exceeded euchromatin and it was located mainly in the membrane with areas of rarefaction in the pore area Conclusion. In 14-day-old intact male rats, the intermediate lobe of the adenohypophysis was presented as a formed functionally active organ. In the ultrastructure of the cytoplasm of melanotropes there was a moderate development of organelles, and judging by the number and size of secretory granules, as well as the density of their content, we can assume that all these cells differed from each other in their functional activity. In 45-day-old intact rats, accumulation of secretory granules was observed in the cytoplasm of melanotropes, especially near the nucleus, which indicated an increase in melanocyte-stimulating hormones synthesis with age. The ultrastructural state of the cytoplasm and nucleus also indicated an increase in functional activity. The ultrastructure of the intermediate lobe cells of the adenohypophysis of rats at the age of 90 days differed from that of younger animals by signs of different functional activity of individual melanotropic cells

scholarly journals Plasminogen activators of the pituitary gland: enzyme characterization and hormonal modulation.

1983 ◽  
Vol 97 (4) ◽  
pp. 1029-1037 ◽  
Author(s):  
A Granelli-Piperno ◽  
E Reich
Keyword(s):  
Pituitary Gland ◽  
De Novo ◽  
Cell Monolayer ◽  
Enzyme Characterization ◽  
Anterior Lobe ◽  
Enzyme Synthesis ◽  
Intracellular Camp ◽  
Intermediate Lobe ◽  
Extracellular Medium ◽  
Hormonal Modulation

We studied plasminogen activator (PA) of the rat pituitary gland in organ and cell monolayer culture. Both anterior and intermediate lobes contain, synthesize and secrete a mixture consisting of the two known types of PA: urokinase and so-called tissue PA. Both enzymes were formed essentially by all PA secreting cells, and PA was identified specifically in mammotrophs, corticotrophs, and luteinizing hormone containing gonadotrophs. Pituitary PA production was modulated on exposure to a variety of biological effectors: anterior lobe PA secretion was stimulated by agents that raised intracellular cAMP concentration; his process depended on de novo enzyme synthesis. Enzyme production was repressed by androgens and glucocorticoids. When anterior lobe cultures were maintained in plasminogen-free media, the extracellular, secreted forms of ACTH consisted almost exclusively of the high molecular weight forms (31,000 and 23,000); the smaller forms (13,000 and 4,500) were also found in the extracellular medium of cultures supplemented with plasminogen. In contrast, the size distribution of intracellular ACTH species was unaffected by the presence of plasminogen. These results resemble those previously obtained with pancreatic islets and are consistent with the possibility that plasmin, generated by PA secretion, participates in prohormone processing. PA synthesis in intermediate lobe explants was stimulated by exposure to dibutyryl cAMP, and repressed by hydrocortisone. In accordance with the dopaminergic control of intermediate lobe function in some vertebrates, apomorphine strongly repressed PA synthesis in intermediate, but not anterior lobe cultures.

Effects of TRH, prolactin and TSH on cell proliferation in the intermediate lobe of the rat pituitary gland

1996 ◽  
Vol 148 (2) ◽  
pp. 193-196 ◽  
Author(s):  
T Pawełczyk ◽  
M Pawlikowski ◽  
J Kunert-Radek
Keyword(s):  
Cell Proliferation ◽  
Body Weight ◽  
Pituitary Gland ◽  
Anterior Lobe ◽  
Intermediate Lobe ◽  
Proliferating Cells ◽  
Rat Pituitary ◽  
Trh Analogues ◽  
Intermediate Pituitary Lobe ◽  
Significant Stimulatory Effect

Abstract The effect of TRH on cell proliferation in the anterior lobe of the pituitary is well known and documented. On the other hand, there are no data on the effects of TRH on the intermediate lobe of the pituitary gland. The aim of this study was to investigate the effect of TRH and its analogues (pGlu-His-Gly, pGlu-His-Gly-NH2) on cell proliferation in the intermediate pituitary lobe. The bromodeoxyuridine technique was used to detect the proliferating cells. It was found that TRH stimulated cell proliferation 24 h after a single injection at a dose of 100 μg/kg body weight. The TRH analogues did not exert any significant stimulatory effect either 12 h or 24 h after the injection. The second experiment was carried out to distinguish the probable mechanism of the action of TRH. The effects of TSH and prolactin (PRL) on intermediate lobe cell proliferation were examined. It was found that both PRL and TSH exerted a significant stimulatory effect 24 h after a single s.c. injection of PRL at a dose of 150 IU/kg body weight or TSH at a dose 20 IU/kg body weight. It therefore appears that the stimulatory effect of TRH on intermediate pituitary lobe cell proliferation is mediated by PRL and TSH. Journal of Endocrinology (1996) 148, 193–196

Sign in / Sign up

Export Citation Format

Share Document