Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The sexually dimorphic profile of GH secretion is thought to be engendered by gonadal steroids acting in part on hypothalamic periventricular somatostatin (SOM) neurons. The present study set out to examine and characterize the development of sex differences in these SOM neurons. In the first series of experiments, we used in situ hybridization to examine SOM messenger RNA (mRNA) expression within the periventricular nucleus (PeN) of male and female rats on postnatal day 1 (P1), P5, and P10. Cellular SOM mRNA content was found to increase from P1 to P10 in both sexes (P < 0.01), but was 24% (P < 0.05) and 38% (P < 0.01) higher in males on P5 and P10, respectively. A second series of experiments examined the SOM peptide content of the PeN in developing rats and found increasing levels from P1 to P10, with a 44% higher SOM content in males compared with females on P10 (P < 0.05). The third series of experiments questioned the role of gonadal steroids in engendering sex differences in SOM mRNA expression by determining the effects of neonatal gonadectomy (GDX) and replacement of dihydrotestosterone or estradiol benzoate. The SOM mRNA content of PeN neurons in P5 males gonadectomized on the day of birth was the same as that in P5 females and was significantly reduced compared with that in sham-operated P5 males (P < 0.05). Male rats GDX on P1 and treated with estradiol benzoate from P1 to P5 had cellular SOM mRNA levels similar to those in intact males on P5, whereas dihydrotestosterone treatment had no effect. Treatment of intact males with an androgen receptor antagonist, cyproterone acetate, on P1 had no effect on cellular SOM mRNA on P5, whereas male rats given the aromatase inhibitor 1,4,6-androstatriene-3,17-dione from P1 to P5 had lower (P < 0.05) SOM mRNA levels than controls. In the final set of experiments, dual labeling immunocytochemistry showed that SOM neurons in the PeN of P5 rats did not contain estrogen receptor-alpha, but expressed androgen receptors in a sexually dimorphic manner. These results demonstrate that a sex difference in SOM biosynthesis, which persists into adulthood, develops between P1 and P5 in PeN neurons. Despite the absence of estrogen receptor-alpha in these neurons, the organizational influence of testosterone only occurs after its aromatization to estrogen.
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PMID:Estrogen-dependent ontogeny of sex differences in somatostatin neurons of the hypothalamic periventricular nucleus. 949 79

Though sex steroids are found to influence thyroid pathogenesis in human and in animals, their role in normal thyroid growth and thyrocyte proliferation is not yet understood fully. The present study is addressed to know the effect of testosterone and estradiol on the basal and TSH-induced thyrocyte proliferation in immature and adult rats in vitro. The male and female Wistar rats were gonadectomized (GDX) and one group of GDX rats were supplemented with either testosterone or estradiol. After the experimental period, the rats were sacrificed by decapitation and thyroid glands were removed, washed in Hank's Balanced Salt Solution (HBSS), pH 7.4 and digested with the enzyme mixture containing 0.08% collagenase and 0.12% dispase in HBSS. The isolated follicles were washed thrice with Dulbecco's modified Eagle's medium (DMEM) containing 0.5% fetal bovine serum (FBS), and were cultured in Falcon's tissue culture flasks containing 5 ml DMEM with FBS (5%) transferrin (5 microg/ml), hydrocortisone (10(-8) M), somatostatin (10 microg/ml), insulin (10 microg/ml) and glycyl-L-histidyl-L-lysine acetate (10 microg/ml). The cells (2.5 x 10(4)) were exposed to various exponential doses of TSH or testosterone (6.25-800 ng/ml) or estradiol (6.25-800 pg/ml). It is suggested from the present study that both TSH and sex steroids enhance thyrocyte proliferation. The mitogenic effect of TSH is greater than that of sex steroids. Sex steroids modulate TSH-induced cell proliferation in a gender-specific manner.
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PMID:Testosterone and estradiol differentially regulate TSH-induced thyrocyte proliferation in immature and adult rats. 1199 29