Knecht M, Tsai-Morris C H, Catt K J
Endocrinology. 1985 May;116(5):1771-7. doi: 10.1210/endo-116-5-1771.
In rat ovarian granulosa cells cultured for 48 h, addition of 10(-8) M estradiol (E2) enhanced choleragen-induced cAMP formation and LH receptor content by 2-fold and 6-fold, respectively. Two potent antiestrogens, tamoxifen and keoxifene, inhibited these effects of E2 in a concentration-dependent manner and significantly reduced cAMP production and LH receptors below the levels induced by choleragen. Both antiestrogens (greater than or equal to 1 microM) also reduced the effects of choleragen on cAMP levels and LH receptor content in the absence of exogenous E2. In addition, the antiestrogens (1 microM) inhibited the stimulatory effects of FSH and forskolin on granulosa cell maturation, as well as the enhancement of their actions by exogenous E2. FSH caused a concentration-dependent rise in endogenous E2 accumulation during the 48-h culture period, suggesting that antiestrogens may prevent FSH-stimulated increases in LH receptors by inhibiting the actions of newly formed E2. Tamoxifen prevented the induction of LH receptors by 8-bromo-cAMP, indicating that its effects were on both cAMP production and cAMP action, whereas keoxifene predominantly altered granulosa cell development by its inhibition of estrogen effects on cAMP production. Although both exogenous E2 and the antiestrogens modified cAMP accumulation and LH receptor expression largely during the second 24 h of culture, their actions commenced during the first day. The antiestrogens had no effect alone and did not reduce the DNA content of granulosa cells. Also, they could be washed from the cells after 48 h of culture with complete recovery of forskolin-stimulated cAMP responsiveness by 72-96 h of culture. At a lower concentration (0.4 microM), tamoxifen, but not keoxifene, acted as a partial estrogen agonist since it enhanced choleragen action. These results indicate that the cAMP-mediated induction of LH receptors in cultured granulosa cells is dependent upon the continued actions of estrogen throughout the maturation process.
在培养48小时的大鼠卵巢颗粒细胞中，添加10⁻⁸M雌二醇（E2）可使霍乱毒素诱导的cAMP生成和LH受体含量分别增加2倍和6倍。两种强效抗雌激素药物他莫昔芬和凯昔芬以浓度依赖的方式抑制E2的这些作用，并使cAMP生成和LH受体显著低于霍乱毒素诱导的水平。在没有外源性E2的情况下，两种抗雌激素药物（≥1μM）也降低了霍乱毒素对cAMP水平和LH受体含量的影响。此外，抗雌激素药物（1μM）抑制了FSH和福斯高林对颗粒细胞成熟的刺激作用，以及外源性E2对其作用的增强。FSH在48小时培养期内导致内源性E2积累呈浓度依赖性增加，这表明抗雌激素药物可能通过抑制新生成的E2的作用来阻止FSH刺激的LH受体增加。他莫昔芬可阻止8-溴-cAMP诱导LH受体，这表明其作用于cAMP生成和cAMP作用两方面，而凯昔芬主要通过抑制雌激素对cAMP生成的作用来改变颗粒细胞发育。尽管外源性E2和抗雌激素药物在很大程度上在培养的第二个24小时内改变了cAMP积累和LH受体表达，但它们的作用在第一天就开始了。抗雌激素药物单独使用无作用，也不降低颗粒细胞的DNA含量。此外，在培养48小时后可将它们从细胞中洗脱，到培养72 - 96小时时福斯高林刺激的cAMP反应性可完全恢复。在较低浓度（0.4μM）时，他莫昔芬而非凯昔芬作为部分雌激素激动剂起作用，因为它增强了霍乱毒素的作用。这些结果表明，培养的颗粒细胞中cAMP介导的LH受体诱导依赖于雌激素在整个成熟过程中的持续作用。
