Maxson W S, Haney A F, Schomberg D W
Biol Reprod. 1985 Sep;33(2):495-501. doi: 10.1095/biolreprod33.2.495.
To evaluate the mechanisms involved in the reduction of estrogen concentrations in porcine follicular fluid during atresia, nonatretic and atretic follicles ranging from 4 to 7 mm in diameter were selected. Follicular fluid estrogen concentrations were 7-16-fold less in the atretic follicles. Isolated granulosa cells from atretic follicles demonstrated a significant reduction in aromatase activity and in follicle-stimulating hormone (FSH)-induced progesterone production in vitro compared to granulosa cells from nonatretic follicles. Isolated theca from atretic follicles also demonstrated a reduction in estrogen production. However, androgen concentrations were equivalent in the follicular fluid of atretic and nonatretic follicles, and theca from atretic follicles maintained testosterone and androstenedione production in vitro. The loss of thecal aromatase activity with atresia is not secondary to a reduction in FSH responsiveness, since FSH did not increase thecal progesterone production in vitro. Cell degeneration also does not account for the reduction in thecal estrogen production, since both androgen output in vitro and follicular fluid androgen concentrations were maintained. These data thus demonstrate that a mechanism other than reduced FSH responsiveness must account for the selective loss of thecal aromatase activity in this stage of atresia.
为了评估卵泡闭锁过程中猪卵泡液中雌激素浓度降低所涉及的机制，选取了直径为4至7毫米的非闭锁卵泡和闭锁卵泡。闭锁卵泡中的卵泡液雌激素浓度低7至16倍。与非闭锁卵泡的颗粒细胞相比，来自闭锁卵泡的分离颗粒细胞在体外的芳香化酶活性以及促卵泡激素（FSH）诱导的孕酮生成均显著降低。来自闭锁卵泡的分离卵泡膜细胞也显示雌激素生成减少。然而，闭锁卵泡和非闭锁卵泡的卵泡液中雄激素浓度相当，并且来自闭锁卵泡的卵泡膜细胞在体外维持睾酮和雄烯二酮的生成。卵泡闭锁时卵泡膜芳香化酶活性的丧失并非继发于FSH反应性降低，因为FSH在体外并未增加卵泡膜孕酮的生成。细胞变性也不能解释卵泡膜雌激素生成的减少，因为体外雄激素输出和卵泡液雄激素浓度均得以维持。因此，这些数据表明，在这个闭锁阶段，除了FSH反应性降低之外，一定存在其他机制导致卵泡膜芳香化酶活性的选择性丧失。
