Research on the Control Mechanism of the Secretion of Ovarian Steroid Hormones

1)垂体前叶促性腺激素的分泌被抑制。RU 486（抗人前列腺素药物）抑制这种抑制。我们在体内和体外都证实了这一点。去氧孕烯（DG）本身无明显作用，但其代谢产物3-酮-DG使促性腺激素酶活性下降。结果表明，孕三烯酮、3-酮-DG对3 β-HSD有抑制作用，达那唑和DG对17，20裂解酶有抑制作用。本实验表明DG直接抑制卵巢类固醇的合成。3）孕鼠卵巢中存在EGF受体。结果表明，EGF能拮抗促性腺激素的促性腺作用，而对P_4、20 α-OH-P_4和cAMP水平无影响。4）妊娠大鼠卵巢内存在胰岛素和IGFs受体。我们用胰岛素或IGFs培养黄体细胞。当IBMX与这些肽一起使用时，它们增加了P_4、20 α-OH-P_4和cAMP的水平。5）RU 486对体外培养的黄体细胞有溶黄体作用，但对去垂体PMS-hCG处理的大鼠血清P_4水平影响不大。因此，在体内观察到的RU 486的强溶黄体作用主要通过垂体发挥。

1) The gonadotropin secretion from the rat anterior pituitary was suppressed by progestin. RU486 (anti progestin drug) inhibited this suppression. We confirmed this both in vivo and in vitro. Desogestrel (DG) had no effect by itself, but 3 keto-DG (the metabolite of DG) decre ased the gonadotropin rease.2) We investigated the effect of synthetic steroids on ovarian enzymes. In conclusion, 3beta-HSD was inhibited by gestrinone, 3 keto-DG and 17,20 lyase was inhibited by danazol and DG. This experiment indicated that DG inhibited the synthesis of ovarian steroids directy.3) There is an EGF receptor in the ovary of pregnant rat. We cocultured luteal cells with EGF for two days and EGF counteracted the tropic effect of gonadotropins without any effect on basal levels of P_4, 20alpha-OH-P_4 and cAMP.4) There are receptors of insulin and IGFs in the ovary of pregnant rats. We cultured luteal cells with insulin or IGFs. When IBMX was used with these peptides, they increased the levels of P_4, 20alpha-OH-P_4 and cAMP. Without IBMX, these peptides had little effect because they stimu lated the activity of cAMP phosphodiesterase.5) RU486 had luteolytic effect on cultured luteal cells, but it had a weak effect on serum P_4 level of the hypophysectomized PMS-hCG treated rat. Therefore the strong luteolytic effect of RU486 observed in vivo was exerted mainly through the pituitary.