Chan W K, Tan C H
Endocrinology. 1986 Nov;119(5):2353-9. doi: 10.1210/endo-119-5-2353.
We examined the effects of T3 and T4 on basal and FSH-induced aromatase activity in granulosa cells isolated from medium-sized follicles (4-6 mm) of prepubertal pigs. Treatment of cells with T3 or T4 alone during an initial 48-h induction period did not result in any significant change in aromatase activity, as measured by 17 beta-estradiol accumulation during the subsequent 6-h test period, when testosterone (0.5 microM) was added as substrate. However, when cells were cultured with FSH and T3 or T4 during the induction period, a definite dose-dependent inhibition of FSH-induced aromatase activity was demonstrated. This inhibition was not altered by the presence of a binding protein (BSA). The inhibition of FSH-induced aromatase activity by T4 and T3 is a true biological effect, as inactive iodocompounds (MIT and DIT) and iodide had no significant effect on the gonadotropin-induced aromatase activity. Furthermore, the viability of cells was unaffected by the thyroid hormones, and total cellular protein did not change significantly. These results indicate that thyroid hormones might play an important role in modulating FSH-induced aromatase activity, and that the elevated plasma estrogen levels in some cases of hyperthyroidism are not due to increased ovarian secretion.
我们研究了T3和T4对从青春期前猪的中等大小卵泡（4 - 6毫米）分离出的颗粒细胞中基础和促卵泡激素（FSH）诱导的芳香化酶活性的影响。在最初的48小时诱导期单独用T3或T4处理细胞，在随后6小时测试期（添加睾酮（0.5微摩尔）作为底物）通过17β-雌二醇积累测量时，芳香化酶活性没有任何显著变化。然而，当细胞在诱导期与FSH以及T3或T4一起培养时，FSH诱导的芳香化酶活性出现了明确的剂量依赖性抑制。这种抑制不受结合蛋白（牛血清白蛋白，BSA）存在的影响。T4和T3对FSH诱导的芳香化酶活性的抑制是一种真正的生物学效应，因为无活性的碘化合物（一碘甲腺原氨酸，MIT和二碘甲腺原氨酸，DIT）和碘对促性腺激素诱导的芳香化酶活性没有显著影响。此外，细胞活力不受甲状腺激素影响，细胞总蛋白也没有显著变化。这些结果表明，甲状腺激素可能在调节FSH诱导的芳香化酶活性中起重要作用，并且某些甲状腺功能亢进病例中血浆雌激素水平升高并非由于卵巢分泌增加所致。
