CHARACTERIZATION OF CORTICOSTERONE FEEDBACK-REGULATION OF ACTH-SECRETION
CHARACTERIZATION OF CORTICOSTERONE FEEDBACK-REGULATION OF ACTH-SECRETION
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DOI：
10.1111/j.1749-6632.1987.tb24976.x
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发表时间：
1987-12-31
影响因子：
5.2
通讯作者：
SHINSAKO, J
中科院分区：
文献类型：
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作者：
DALLMAN, MF;AKANA, SF;SHINSAKO, J
肾上腺切除引起的大鼠ACTH分泌增加是通过皮质酮对大脑的作用恢复正常的，而不是对脑下垂体的作用。肾上腺切除后持续补充类固醇5天后，血浆中可使ACTH下降50%的游离皮质酮浓度约为0.8 nM。相比之下，胸腺湿重减少50%所需的游离血浆皮质酮浓度或血浆转皮质素浓度(两者都是糖皮质激素作用的靶标)约为4.5 NM。这些结果表明，皮质酮对ACTH的抑制可能是通过类固醇与高亲和力的I型皮质醇受体结合而实现的，而对胸腺重量和转皮质素的抑制作用可能是通过类固醇与亲和力较低的II型受体结合而实现的。比较皮质酮、地塞米松和醛固酮抑制肾上腺切除诱导的ACTH分泌的研究结果支持这样的假设，即大鼠基础ACTH的分泌是通过皮质酮与I型受体的联系来调节的。
Adrenalectomy-induced increases in ACTH secretion in rats are returned to normal by an action of corticosterone on the brain, not on the pituitary. Five days after adrenalectomy with constant steroid replacement, the concentration of free corticosterone in plasma which reduces plasma ACTH by 50% is approximately 0.8 nM. By contrast, the concentration of free plasma corticosterone required for 50% reduction of thymus wet weight or plasma transcortin concentration (both targets for glucocorticoid action) is about 4.5 nM. These results suggested that the inhibition of ACTH by corticosterone might be mediated by association of the steroid with high affinity, type I corticosteroid receptors, whereas the inhibition of thymus weight and transcortin might be mediated by association of the steroid with lower affinity, type II receptors. The results of studies comparing the ability of corticosterone, dexamethasone and aldosterone to inhibit adrenalectomy-induced ACTH secretion support the hypothesis that basal ACTH secretion in rats is mediated by association of corticosterone with type I receptors.