Matsuyama S, Shiota K, Takahashi M
Department of Veterinary Physiology, University of Tokyo, Japan.
Endocrinology. 1990 Oct;127(4):1561-7. doi: 10.1210/endo-127-4-1561.
PRL is known to be a hormone carrying luteotropic action in rats and enhances progesterone secretion by suppressing 20 alpha-hydroxysteroid dehydrogenase (20 alpha HSD) activity in the corpus luteum. In this study, we investigated the effects of PRL and transforming growth factor-beta (TGF beta) on the 20 alpha HSD activity of rat luteal cells in vitro and examined whether TGF beta is involved in the luteotropic action of PRL. 20 alpha HSD activity of luteal cells (from midpseudopregnant rats), which had been suppressed by PRL in vivo, increased when the cells were cultured for 48 h without PRL addition. TGF beta (0.01, 0.1, 1.0, and 10.0 ng/ml) as well as PRL (2, 20, 200, and 2000 ng/ml) suppressed this increase in a dose-dependent manner. Furthermore, the suppressive effect of PRL on 20 alpha HSD activity was significantly attenuated by anti-TGF beta antibody. Activin, having homology with TGF beta in its chemical structure, also suppressed the increase in enzyme activity, although the effect was much less marked than that of TGF beta. TGF beta or PRL did not affect total progestin (progesterone plus 20 alpha-dihydroprogesterone) secretion, but induced reduction in 20 alpha-dihydroprogesterone secretion during a 48-h culture period, without any alteration of DNA or protein content per culture dish. These results indicate that TGF beta, like PRL, can suppress luteal 20 alpha HSD activity without producing nonspecific cell damage, and that the luteotropic action of PRL is at least in part mediated by TGF beta or an immunoreactive TGF beta-like substance(s).
已知催乳素（PRL）是一种在大鼠体内具有促黄体生成作用的激素，它通过抑制黄体中的20α-羟类固醇脱氢酶（20αHSD）活性来增强孕酮分泌。在本研究中，我们调查了PRL和转化生长因子-β（TGF-β）对体外培养的大鼠黄体细胞20αHSD活性的影响，并研究了TGF-β是否参与PRL的促黄体生成作用。体内被PRL抑制的黄体细胞（来自妊娠中期假孕大鼠），在无PRL添加的情况下培养48小时后，其20αHSD活性增加。TGF-β（0.01、0.1、1.0和10.0 ng/ml）以及PRL（2、20、200和2000 ng/ml）以剂量依赖的方式抑制了这种增加。此外，抗TGF-β抗体显著减弱了PRL对20αHSD活性的抑制作用。激活素在化学结构上与TGF-β具有同源性，它也抑制了酶活性的增加，尽管其作用比TGF-β弱得多。TGF-β或PRL不影响总孕激素（孕酮加20α-二氢孕酮）的分泌，但在48小时的培养期内诱导20α-二氢孕酮分泌减少，且每个培养皿中的DNA或蛋白质含量没有任何变化。这些结果表明，TGF-β与PRL一样，可以在不产生非特异性细胞损伤的情况下抑制黄体20αHSD活性，并且PRL的促黄体生成作用至少部分是由TGF-β或一种免疫反应性TGF-β样物质介导的。
