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1.
By means of double immunohistochemical techniques and a nonradioisotopic in situ hybridization method, we determined the colocalization pattern of glucocorticoid receptor (GR) and pituitary hormones and the GR messenger RNA (mRNA) expression in the pituitaries of Wistar adult male rats. Immunoreactivity for GR was detected in the nuclei of cells in the anterior and posterior pituitary. Double immunohistochemistry revealed that the colocaliza- tion of GR and anterior pituitary hormones occurred in almost 99% of the growth hormone (GH)-producing cells and adrenocorticotropic hormone (ACTH)-producing cells, and in 67% of the thyroid stimulating hormone (TSH)-producing cells. Almost all of the folliculostellate cells (93%), marginal layer cells (94%) in the anterior pituitary, and pituicytes (96%) in the posterior pituitary immunostained for S100 protein antibody were also immunostained with GR. GR mRNA was abundant in the cytoplasm of anterior and intermediate pituitary cells but scattered sparsely in that of the posterior pituitary. These results suggest that glucocorticoids directly influence certain pituitary cells in order to regulate cell function, including the synthesis and/or secretion of hormones.  相似文献   

2.
3.
Dekanski's method was used to estimate the pressor activity of the extracts of the posterior pituitary lobe in anaesthetized rats, after the infusion of 0.9% NaCl solution above the supraoptic nuclei and haemorrhage in the amount of 1.5% of body weight or after the infusion of Substance P solution above the supraoptic nuclei and haemorrhage. It has been found that the vasopressin content in the posterior pituitary lobe decreased about 20% after the infusion of 0.9% NaCl solution and haemorrhage. The infusion of Substance P above the supraoptic nuclei inhibits the loss of vasopressin from the pituitary caused by haemorrhage.  相似文献   

4.
This study focused on expression of estradiol receptors (ER) during the estrous cycle. Labeling for ERalpha or beta antigens and luteinizing hormone (LH) or follicle-stimulating hormone (FSH) beta-subunits was done on freshly dispersed pituitary cells. The lowest expression of ERalpha and beta was seen in estrus (23% and 12%, respectively). Expression increased to 42-54% of pituitary cells by diestrus. In males, cells with ERalpha or beta were 37% or 20% of the population, respectively. ERalpha or beta and gonadotropin antigens were in 6-9% of pituitary cells from male rats. Early in the cycle (estrus and metestrus), less than 5% of pituitary cells expressed ERalpha or beta with gonadotropins. These values doubled to reach a peak of 10% during proestrus (just before ovulation). These data show that a rise in expression of both ERalpha and ERbeta is a part of preovulatory differentiation of pituitary gonadotropes.(J Histochem Cytochem 49:665-666, 2001)  相似文献   

5.
Fifty-seven children with growth hormone deficiency and 15 healthy age-matched controls were studied by magnetic resonance imaging (MRI). Of the patients, 36 (63%) had isolated GH deficiency (IGHD) and 21 (37%) multiple pituitary hormone deficiency (MPHD). MRI studies showed a marked reduction in pituitary volume in all patients in comparison with normal controls. Moreover, a striking morphological abnormality with the apparent absence of the pituitary stalk and an ectopic posterior pituitary lobe was detected in 34 of the patients (59%). This pituitary stalk abnormality was detected in 95% of the MPHD patients and in 39% of the IGHD patients. All but one of the patients with a normal pituitary stalk had IGHD. Endocrine evaluation showed no correlation with MRI data: in particular patients with an apparent anatomical interruption of the hypothalamic-pituitary axis showed a variety of patterns of hormonal responses. In conclusion, our study shows a high frequency of hypothalamic-pituitary anomalies in patients with GH deficiency, particularly related with MPHD. However, further studies are needed to improve our understanding of the relationship between MRI and endocrine data.  相似文献   

6.
The involvement of the pituitary and mesonephros in oogenesis was examined with the rabbit used as an experimental model. Fetal and neonatal ovaries were cultured for 8 days with and without their corresponding pituitaries or as half cranial or caudal portions. Progression of meiosis was followed histologically and autoradiographically by the uptake of tritiated thymidine. Pulse labeling for 24 h occurred on Days 0, 2, 4 and 7 of culture. No difference was noted in labeling or progression of meiosis in neonatal ovaries with or without the pituitary or in sectioned ovaries. By contrast, fetal ovaries with pituitary that were labeled on Day 4 had a labeling index (positive cells/1000 microns 2 of cortex) of 282.1 +/- 32.9 (mean +/- SEM) compared to 107.1 +/- 24.9 for ovaries without pituitary. Those labeled on Day 7 showed the same differences (263.7 +/- 46.0 vs. 160.2 +/- 20.8). Histologically, there was a threefold difference in percentage of germ cells with pituitary undergoing meiosis (21.2 +/- 2.9% compared to 7.1 +/- 2.8% without). These data suggest that the fetal pituitary has an important role in inducing meiotic prophase in the rabbit.  相似文献   

7.
Genistein对大鼠垂体前叶细胞增殖的抑制作用   总被引:2,自引:0,他引:2  
Zhang QH  Hu YZ  Zhou SS  Wang FZ 《生理学报》2001,53(1):51-54
应用细胞培养、^3H-TdR掺入、流式细胞和电镜技术,观察酪氨酸蛋白激酶(PTK)抑制剂genistein对正常大鼠垂体前叶细胞和垂体瘤细胞株AtT-20增殖的影响,并探讨其可能的机制。结果显示:genistein作用48h后可明显抑制正常大鼠垂体前叶细胞和垂体瘤细胞株AtT-20增殖。流式细胞仪检测发现,50和100μmol/L genistein可将AtT-20细胞阻断于G0/G1期及G2/M期,并出现凋亡峰,凋亡率分别灰19.9%和36.4%。电镜照片显示有凋亡细胞。结果表明,PTK抑制剂可以明显抑制正常大鼠垂体前叶细胞和垂体瘤细胞株AtT-20的殖,并诱导细胞凋亡,说明PTK活性对细胞增殖和分化有重要作用。  相似文献   

8.
OBJECTIVES: The aim of the study was to examine susceptibility of the pituitary gland to estrogenic impulse in old, noncycling rats by measurement of steady state level of mRNAs encoding LH subunits a and b and mRNA for PRL. METHODS: 22-month-old rats were ovariectomized and after one week they were subcutaneously implanted with silastic tubing filled with oil or with estradiol 17-beta. Pituitary alpha, LHbeta and PRL mRNAs content and serum LH and PRL concentration was determined. RESULTS: The effect of E (2)treatment was manifested by the significant increase in the weight of the uterus and pituitary gland as well as by elevation of total pituitary RNA (109%, 60% and 78%, respectively; p<0.001). No significant changes (p>0.05) in serum LH concentration were observed, while levels of mRNAs encoding alpha and LH-beta subunits were lowered by 54% (p<0.05) and 96% (p<0.01), respectively, in the rats subjected to E(2) stimuli. No direct correlation between synthesis and release of LH in E(2) treated old rats was observed. The blood PRL concentration and the pituitary level of PRL mRNA increased up to 2,000% and 1,300%, respectively (p<0.001). Spontaneous pituitary adenoma was observed in about 30% of the rats, irrespective of treatment. CONCLUSIONS: These data show that in old rats estrogenic stimulus can effectively diminish both pituitary LH subunits mRNAs as well as stimulate pituitary PRL mRNA level indicating that the E(2)-dependent processes involved in the regulation of corresponding genes are still functional.  相似文献   

9.
Steady-state analysis of the acid extracts of the intermediate pituitary of the toad, Bufo marinus, revealed the presence of multiple forms of beta-endorphin and alpha-MSH. Approximately 98% of the immunoreactive beta-endorphin was N-acetylated. The major form of N-acetylated beta-endorphin, which represented 81.5% of the total beta-endorphin recovered from this tissue, had an apparent molecular weight of 1.2 kDa and a net charge of +1 at pH 2.75. Approximately 98% of the immunoreactive alpha-MSH present in the Bufo intermediate pituitary had reverse phase HPLC properties similar to the nonacetylated form of alpha-MSH, ACTH(1-13)amide. These observations are in agreement with studies on the intermediate pituitary of the frog, Xenopus laevis, which have shown that the N-acetylation of alpha-MSH in this species is a cosecretory processing event, whereas the N-acetylation of beta-endorphin is a posttranslational processing event (2, 5, 15). These observations indicate that the N-acetylation of beta-endorphin and alpha-MSH occurs at distinct subcellular sites in intermediate pituitary cells of anuran amphibians. The Bufo intermediate pituitary will serve as a good model system for studying these novel N-acetyltransferase reactions.  相似文献   

10.
Using the indirect immunofluorescence test for the detection of pituitary autoantibodies in human serum, the results obtained with human fetal and non-human pituitary antigens were compared. Of the sera that were positive on human fetal substrate, 4% were recovered with adult baboon, 0% with fetal cymologous, 20% with porcine, 11% with bovine, 11% with ovine, and 7% with rat tissue. The rate of heterophilic antibodies to the above animal substrates was 5% to 14%. In contrast to human adult pituitaries, normal human sera did not bind to Fc receptors on ACTH-cells of human fetal pituitaries. This allowed the demonstration of ACTH-cell antibodies. The specificity of the reaction was proven by absorption studies with purified Fc fragments. These results suggest that human fetal tissue is the best source of antigen for the detection of pituitary autoantibodies. The use of animal tissue including non-human primate pituitary yields results that bear no clinical significance.  相似文献   

11.
To explore the expression of androgen receptor (AR) and estrogen receptor alpha (ERα) in the developing pituitary of male lamb, we detected AR and ERα expression in the anterior pituitary of lambs aged 2-7 months old by immunohistochemistry. The results showed that both AR immunoreactivity (AR-ir) and ERα immunoreactivity (ERα-ir) were localized in the nuclei of anterior pituitary cell. The percentage of the anterior pituitary cells expressing ERα fluctuated from 8.79±0.02% to 11.80±0.04% during the examined stages, but fell significantly to the lowest level at 6 months. While the proportion of AR-ir showed significant changes, it was in 11.52±1.26% at 2 months, it firstly increased to 19.86±1.03% at 3 months, and then significantly decreased to 8.18±1.17% at 6 months (P<0.05). The expression of both AR-ir and ERα-ir were the lowest level at 6 months old. By staining for PCNA, we observed that the changes in expression of AR and ERα at different lamb ages did not result from cell proliferation of anterior pituitary cells. These results indicate that both AR and ERα are important in regulation of secretary function of anterior pituitary in sheep lamb, although the related mechanism needs to be elucidated further.  相似文献   

12.
Cimini V 《Peptides》2000,21(11):1711-1716
Immunocytochemical analysis of endocrine cells of the developing rat pituitary has shown clearly that, starting from E16, the galanin-immunoreactive cells are heterogeneous, the neuropeptide being present in cells containing the majority of pituitary hormones. A proportion of galanin-containing corticotropes, starting from about 17% at E16 reached about 29% at E21, while the galanin-containing lactotrope increase in the same period was from about 13% to 34%. Galanin-containing thyrotropes ranged from about 11% at E16 to about 13% at E21, while the proportion of galanin-containing luteotropes increased consistently from about 17% at E19 to about 27% at E21. Only the trend of galanin-containing somatotropes was inverted, falling from about 26% to 13%. We conclude that the multiple coexistence of galanin with most of the pituitary hormones during fetal development is a further example of plasticity of endocrine pituitary cells, and that galanin may have a role in cytodifferentiation.  相似文献   

13.
We measured glycosylated PRL (G-PRL) in the pituitary gland and plasma of lean and obese barrows (castrated male pigs) by immunoblotting. We found that G-PRL constituted 40% or more of total monomeric PRL in the pituitary gland of these animals. Furthermore, pituitary G-PRL concentrations in obese barrows averaged 58% higher than in those of lean controls. The non-glycosylated PRL concentrations were also higher in the pituitaries of obese barrows in comparison to lean controls, but the magnitude of the difference was smaller (42%). Plasma concentrations of the two forms, or total immunoreactive PRL measurable by radioimmunoassay, did not differ significantly between the two groups. The pituitary data suggest that the state of PRL secretion is altered in obese barrows, and that the alteration is more pronounced for G-PRL than for the non-glycosylated counterpart.  相似文献   

14.
Affinity chromatography on concanavalin A-Sepharose is a time saving step in both large and small scale isolations of the bovine pituitary glycoprotein hormones. After ion-exchange chromatography, the final yield of purified lutropin is 40-50% of material in starting concentrates and of purified thyrotropin is approximately 20%. The final products have the same electrophoretic and immunological properties and amino acid compositions as previous preparations. Less than 3% of the immunoreactive lutropin, follitropin and thyrotropin are present as non-glycosylated forms in either crude pituitary extracts or concentrates. Thyrotropin and follitropin elute from the immobilized lectin as a single fraction, whereas lutropin separates into two glycosylated fractions. Gel filtration of both crude extracts and the glycoprotein fractions shows that less than 5% of the immunoreactivity of the hormones is present as material of apparently high molecular weight. Substantial alpha subunit immunoreactivity, however, is in three fractions (as found by others in human pituitary extracts) corresponding to "high molecular weight material" (7%), intact hormones (46%) and free subunit (47%).  相似文献   

15.
In gonadectomized rats of either sex s.c. administration of 5 alpha-dihydrotestosterone (DHT) reversed, in a dose dependent manner, effects brought about by gonadectomy: it decreased pituitary wet weight and serum levels of LH and FSH and suppressed microsomal enzyme activities involved in testosterone and progesterone metabolism in the pituitary gland, NADPH-linked 5 alpha-reductase and NADH-linked 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSDH). Concomitantly administered nonsteroidal antiandrogen, flutamide (5 mg/day), antagonized some of the suppressive effects induced by a 14-day treatment of gonadectomized rats with high dose (1 mg/day) of DHT. It completely blocked DHT action on pituitary 5 alpha-reductase activity in the female rat and, in the male, inhibition was found to be 30-35%. In male, but not female rats, it completely blocked DHT suppression of serum FSH level whereas it slightly, but significantly inhibited DHT suppression of serum LH in rats of either sex. However, flutamide did not prevent DHT suppression of pituitary wet weight or NADH-linked 3 alpha-HSDH activity. Concomitantly administered progestational antiandrogen, cyproterone acetate (5 mg/day), inhibited DHT-induced weight increase of seminal vesicles by 50-55% and completely blocked the weight decrease of pituitary gland but did not antagonize DHT suppression of serum gonadotropins or pituitary enzyme activities. The results obtained with flutamide suggest that DHT-induced suppression of pituitary NADPH-linked 5 alpha-reductase, but not NADH-linked 3 alpha-HSDH activity, might involve an androgen receptor mechanism.  相似文献   

16.
Weanling female litter mates were equally proportioned at the start of the study between a breeding and a non-breeding group. At 10 weeks of age, each rat of the breeding group was housed individually with a male until 5 litters were produced (or exceptionally for a maximum of 42 weeks) before the male was removed. Females of the non-breeding group were kept singly in similar cages. 2 years after the start of the study all the surviving rats of both groups were killed. Comprehensive necropsies were performed on the decedents and survivors and the pituitary gland of each rat was examined histologically. The 48% survival of the female rats which were allowed to breed was better, but not significantly so, than the 38% of those not allowed to breed. Overall fewer, 70% (35 of 50) of the mated female rats had pituitary tumours compared with 80% (40 of 50) of the non-mated group. Fewer of the decedents, 69% (18 of 26), of the mated females had pituitary tumours compared with 94% (29 of 31) in the decedents of the non-mated group. More survivors, 71% (17 of 24), of the mated females had pituitary tumours compared with 58% (11 of 19) of the surviving non-mated rats. A tumour was first observed at day 328 in the non-mated group, whilst in the mated group the first tumour was identified at day 450. It is suggested that breeding delays the appearance of pituitary tumours in the female rat.  相似文献   

17.
The aim of this study was to determine whether atrial natriuretic peptide (ANP) alters beta-endorphin (beta-END) secretion from rat intermediate pituitary and whether this effect is a direct action on the intermediate pituitary or an indirect one mediated by hypothalamic factor(s). We studied the release of beta-END from rat neuro-intermediate lobes of the pituitary (NIL) and from the hypothalamo-neurohypophysial complex (HNC), which consists of the hypothalamus, pituitary stalk, intermediate and posterior lobes of the pituitary, by means of an in vitro perifusion system. NIL and HNC were prepared from male Wistar rats and individually perifused for 30 min with perifusion medium followed by 20 min perifusion with medium containing alpha-rat ANP and/or dopamine (DA). Samples of perifusion medium were collected every 5 min and subjected to RIA for beta-END. The basal release of beta-END from NIL was 180% of that from HNC (p less than 0.01), which provides further support for the presence of hypothalamic factors that inhibit beta-END release from the intermediate pituitary. The perifusion of HNC with ANP at 10(-7) and 10(-6) M increased the beta-END concentration by 25 and 50%, respectively (p less than 0.01). In contrast, ANP (10(-8) to 10(-6) M) had no effect on beta-END release from NIL. The inhibitory effect of DA (10(6) M) on beta-END release from NIL and HNC (51% and 50% of the basal release, respectively, p less than 0.01) was confirmed. However, this inhibitory effect was not reversed by ANP.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
Melanin-concentrating hormone (MCH), a 19-amino acid orexigenic (appetite-stimulating) hypothalamic peptide, is an important regulator of energy homeostasis. It is cleaved from its precursor prepro-MCH (ppMCH) along with several other neuropeptides whose roles are not fully defined. Because pituitary hormones such as growth hormone (GH), ACTH, and thyroid-stimulating hormone affect body weight and composition, appetite, insulin sensitivity, and lipoprotein metabolism, we investigated whether MCH exerts direct effects on the human pituitary to regulate energy balance using dispersed human fetal pituitaries (21-22 wk gestation) and cultured GH-secreting adenomas. We found that MCH receptor-1 (MCH-R1), but not MCH receptor-2, is expressed in both normal (fetal and adult) human pituitary tissues and in GH cell adenomas. MCH (10 nM) stimulated GH release from human fetal pituitary cultures by up to 62% during a 4-h incubation (P < 0.05). Interestingly, neuropeptide EI (10 nM), which is also cleaved from ppMCH, increased human GH secretion by up to 124% in fetal pituitaries. A milder, albeit significant, induction of GH secretion by MCH (20%) was seen in cultured GH-secreting pituitary adenomas. A comparable stimulation of GH secretion was seen when cultured mouse pituitary cells were treated with MCH. Treatment of cultured GH adenoma cells with MCH (100 nM) induced extracellular signal-regulated kinases 1 and 2 phosphorylation, suggesting activation of MCH-R1. In aggregate, these data suggest that MCH may regulate pituitary GH secretion and imply a potential cross-talk mechanism between appetite-regulating neuropeptides and pituitary hormones.  相似文献   

19.
In the rat's anterior pituitary, mitoses occur to be side by side, forming "pairs", the frequency of which is significant all the more as their number is underrated in sections. In 85% of the pairs the mitoses are synchronous. These paired synchronous mitoses are suggestive of the existence of cellular clones in the pituitary.  相似文献   

20.
The effects of estradiol benzoate (EB) and testosterone propionate (TP) on pituitary and plasma concentrations of follicle stimulating hormone (FSH) and the in vitro synthesis of FSH in pituitary tissue was studied in mature male rats. By the 4th day of treatment with EB, pituitary content and concentration of FSH had declined, and content had fallen to 6% and concentration to 3% of pretreatment values. Similar results occurred during in vitro synthesis. However, serum levels of FSH did not show any decline until the 21st and 28th days of treatment. Administration of TP produced a progressive increase in pituitary content and concentration of FSH, though serum levels remained unchanged for the 1st 7 days, after which they fell slightly. The effect of TP on the in vitro synthesis of FSH showed no consistent pattern, though in no case was a decrease in the uptake of labeled leucine into immunoprecipitable FSH observed. The results suggest that EB and TP have different effects on pituitary FSH in normal adult male rats.  相似文献   

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