Johnson D C, Tsai-Morris C H, Hoversland R C
Steroids. 1981 Nov;38(5):581-92. doi: 10.1016/0039-128x(81)90056-8.
Immature hypophysectomized rats were injected with 2mg of diethylstilbestrol to increase granulosa cell numbers and with 20 IU of PMS to stimulate ovarian growth. Steroid 17 alpha-hydroxylase activity of cultured granulosa cell, harvested from mature follicles 48 h after injection of PMS, was demonstrated using a tritium exchange assay with 17 alpha 3H-pregneneolone as substrate. For comparison, aromatase activity of the same cells was examined by a similar assay using 1 beta 3H-testosterone as the substrate. The activities of the two enzymes were similar when expressed in terms of the amount of substrate converted per unit time. While an NADPH generating system in the incubation medium was essential for demonstrating any hydroxylase activity, 10-15% of the total aromatase activity could be found without added cofactor. Attempts to alter hydroxylase activity of granulosa cells by inclusion of LH, FSH or prolactin in the incubation medium were unsuccessful. However, activity could be change by prostaglandins (PG) or agents which can alter PG synthesis. Activity was increased by low concentrations of phospholipase A2 (PLA2), histamine, and arachidonic acid (AA). Large doses of PLA2, or AA, were inhibitory. PGE2, but not PGF2 alpha, increased, while indomethacin decreased, hydroxylase activity. The results clearly indicate that granulosa cells in the rat have a potent 17-hydroxylase system and therefore do not support the widely held contention that lack of this enzyme is one of the bases for the need for two kinds of cells for ovarian estrogen production.
对未成熟的垂体切除大鼠注射2毫克己烯雌酚以增加颗粒细胞数量，并注射20国际单位的孕马血清促性腺激素以刺激卵巢生长。在注射孕马血清促性腺激素48小时后，从成熟卵泡中收集培养的颗粒细胞，以17α-3H-孕烯醇酮为底物，采用氚交换试验测定其类固醇17α-羟化酶活性。作为对照，用类似的试验以1β-3H-睾酮为底物检测相同细胞的芳香化酶活性。当以单位时间内转化的底物量表示时，这两种酶的活性相似。虽然孵育培养基中的NADPH生成系统对于证明任何羟化酶活性都是必不可少的，但在不添加辅因子的情况下可以发现总芳香化酶活性的10 - 15%。试图通过在孵育培养基中加入促黄体生成素、促卵泡生成素或催乳素来改变颗粒细胞的羟化酶活性未成功。然而，活性可以被前列腺素（PG）或能改变PG合成的试剂所改变。低浓度的磷脂酶A2（PLA2）、组胺和花生四烯酸（AA）可增加活性。大剂量的PLA2或AA具有抑制作用。前列腺素E2可增加羟化酶活性，而前列腺素F2α则无此作用，吲哚美辛可降低羟化酶活性。结果清楚地表明，大鼠的颗粒细胞具有有效的17-羟化酶系统，因此不支持广泛持有的观点，即缺乏这种酶是卵巢雌激素产生需要两种细胞的基础之一。
