Fanjul L F, Ruiz de Galarreta C M, Hsueh A J
Biol Reprod. 1984 May;30(4):903-12. doi: 10.1095/biolreprod30.4.903.
The mechanism by which estrogens enhance gonadotropin-stimulated ovarian progestin production was investigated by studying the modulation of pregnenolone biosynthesis as well as the activities of 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) and 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) in cultured rat granulosa cells. Cells from immature hypophysectomized, estrogen-treated rats were cultured for 3 days with follicle-stimulating hormone (FSH) and/or estrogens. Pregnenolone production was measured in the presence of cyanoketone which inhibits 3 beta-HSD activity. Activities of 3 beta-HSD and 20 alpha-HSD were determined in cell homogenates by direct enzyme assays. Some cells were also primed with FSH to induce luteinizing hormone (LH) receptors for studies on the effects of estrogens on LH-modulated parameters. Pregnenolone production by cultured granulosa cells was stimulated by FSH, while treatment with diethylstilbestrol (DES) or estradiol further enhanced the gonadotropin action. Treatment with FSH increased 3 beta-HSD activity. Similarly, concomitant treatment with DES further enhanced 3 beta-HSD activity in a dose-dependent manner with an apparent ED50 of 10(-8) M. Also, treatment with estrogens alone increased 3 beta-HSD activity. The increases in enzyme activity induced by estrogen alone or in combination with FSH were not associated with changes in the apparent Km values. FSH also stimulated 20 alpha-HSD activity by 2-fold in these cells, while concomitant treatment with DES did not affect the FSH action. In FSH-primed cells, LH stimulated pregnenolone production while the LH action was enhanced by concomitant treatment with the estrogens. Likewise, LH stimulated the activity of 3 beta-HSD, while concomitant DES treatment further augmented LH action. LH did not stimulate 20 alpha-HSD activity when added alone or in combination with DES. Thus, the estrogen enhancement of the gonadotropin-stimulated progesterone production in cultured rat granulosa cells is associated with increases in pregnenolone biosynthesis and the activity of the 3 beta-HSD enzyme, without affecting the 20 alpha-HSD activity.
通过研究孕烯醇酮生物合成的调节以及培养的大鼠颗粒细胞中3β-羟基类固醇脱氢酶（3β-HSD）和20α-羟基类固醇脱氢酶（20α-HSD）的活性，对雌激素增强促性腺激素刺激的卵巢孕激素产生的机制进行了研究。将来自未成熟垂体切除、经雌激素处理的大鼠的细胞与促卵泡激素（FSH）和/或雌激素一起培养3天。在存在抑制3β-HSD活性的氰基酮的情况下测量孕烯醇酮的产生。通过直接酶法测定细胞匀浆中3β-HSD和20α-HSD的活性。一些细胞也用FSH预处理以诱导促黄体生成素（LH）受体，用于研究雌激素对LH调节参数的影响。培养的颗粒细胞产生的孕烯醇酮受到FSH的刺激，而用己烯雌酚（DES）或雌二醇处理进一步增强了促性腺激素的作用。用FSH处理可增加3β-HSD的活性。同样，DES联合处理以剂量依赖方式进一步增强3β-HSD活性，表观ED50为10^(-8) M。此外，单独用雌激素处理也可增加3β-HSD活性。单独或与FSH联合使用雌激素诱导的酶活性增加与表观Km值的变化无关。FSH还使这些细胞中的20α-HSD活性提高了2倍，而DES联合处理不影响FSH的作用。在FSH预处理细胞中，LH刺激孕烯醇酮的产生，而雌激素联合处理增强了LH的作用。同样，LH刺激3β-HSD的活性，而DES联合处理进一步增强了LH的作用。单独添加或与DES联合添加时，LH均不刺激20α-HSD活性。因此，雌激素增强培养的大鼠颗粒细胞中促性腺激素刺激的孕酮产生与孕烯醇酮生物合成增加和3β-HSD酶活性增加有关，而不影响20α-HSD活性。
