Sex difference in glucocorticoid binding in rat pituitary is estrogen dependent.
Sex difference in glucocorticoid binding in rat pituitary is estrogen dependent.
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DOI：
10.1016/0024-3205(90)90340-w
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发表时间：
1990
期刊：
影响因子：
6.1
通讯作者：
B. B. Turner-B.
中科院分区：
文献类型：
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作者：
B. B. Turner-B.
在处死前12 h切除肾上腺的成年雄性和雌性大鼠的个体垂体中评估了皮质类固醇结合的性别依赖性差异。在LH-20柱上一式两份测定可溶性结合。性腺完整的雌性大鼠的3 H-地塞米松结合率显著低于性腺完整的雄性大鼠（p< 0.01）。这种差异在第二项研究中得到证实（p<.001）。然而，当卵巢切除的女性与性腺切除的男性相比，受体浓度没有差异。雌激素能够逆转卵巢切除术的效果：接受雌激素（10 ug/大鼠/天）的卵巢切除雌性动物的受体明显少于完整雄性动物; p< 0.01）。孕激素（500 μ g/只/天）不能拮抗雌激素对垂体的作用。在I型（盐皮质激素）受体亚群中也发现了性别差异，其约占总受体的10%，女性的受体少于男性。这些结果表明，在垂体中，功能性皮质类固醇受体的水平受到循环雌激素水平的20%下调。这就提出了一种可能性，即女性受体数量较少可能会降低其对垂体水平糖皮质激素负反馈效应的敏感性。
Sex-dependent differences in corticosteroid binding were assessed in individual pituitaries from adult male and female rats that had been adrenalectomized 12 h before sacrifice. Soluble binding was assayed in duplicate on LH-20 columns. Gonadally intact females showed significantly less3H-dexamethasone binding than did intact males (p< 0.01). This difference was confirmed in a second study (p<.001). However, when ovariectomized females were compared with gondadectomized males, there was no difference in receptor concentration. Estrogen was able to reverse the effect of ovariectomy: ovariectomized females receiving estrogen (10ug/rat/day) had significantly fewer receptors than intact males; p< 0.01). Progesterone (500ug/rat/day) did not antagonize the effect of estrogen in the pituitary. A sex difference was also found in the Type I (mineralocorticoid) receptor subpopulation which comprised approximately 10% of the total receptors, with females having fewer receptors than males. These results demonstrate that in the pituitary, the level of functional corticosteroid receptors is subject to a 20% down-regulation by circulating levels of estrogen. This raises the possibility that the lower number of receptors in females may act to reduce their sensitivity to the negative feedback effects of glucocorticoids at the level of the pituitary.