In vitro effects of high molecular weight forms of ACTH on the fetal sheep adrenal
In vitro effects of high molecular weight forms of ACTH on the fetal sheep adrenal
复制标题
高分子量促肾上腺皮质激素对胎羊肾上腺的体外影响
作者：
M. Roebuck;Colin T. Jones;D. Holland;R. Silman
垂体-肾上腺轴直接参与分娩已经得到了很好的证实，至少在绵羊中是这样，并且它的切除会导致妊娠1，2。作为该过程的一部分，胎羊肾上腺在10-15天的胎儿期内迅速生长，并与血浆皮质类固醇浓度的大幅上升相关3，4。这似乎不是由于ACTH分泌增加5，6。胎儿肾上腺在体内似乎难治循环促肾上腺皮质激素，并显示血浆浓度升高反应差1，2，7-9。因此，肾上腺肥大和分娩开始的信号仍不清楚。胎儿肾上腺对促肾上腺皮质激素的反应性已经用分离的肾上腺细胞重新检查。这项研究表明，在胎羊中，这些并不是天生对ACTH无反应，而是高分子量形式的ACTH阻断了ACTH 1 -39的作用。这些肽可能负责控制肾上腺的活性。
The direct involvement of the pituitary–adrenal axis in birth has been well established, at least in sheep, and its removal prolongs pregnancy1,2. As part of the process the fetal sheep adrenal grows rapidly during the 10–15 d prepartum and is associates with a large rise in the plasma corticosteroid concentration3,4. This does not seem to result from an increased ACTH secretion5,6. The fetal adrenal in vivo seems refractory to circulating ACTH and shows poor response to elevation of plasma concentration1,2,7–9. Thus the signal for the adrenal hypertrophy and the initiation of parturition remains unclear. The responsiveness of the fetal adrenal to ACTH has been re-examined using isolated adrenal cells. The study shows that in the fetal sheep these are not inherently unresponsive to ACTH, but that high-molecular-weight forms of ACTH block the action of ACTH1–39. These peptides may be responsible for controlling the activity of the adrenal in situ.