Steroidogenesis in porcine atretic follicles: loss of aromatase activity in isolated granulosa and theca.
Steroidogenesis in porcine atretic follicles: loss of aromatase activity in isolated granulosa and theca.
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DOI：
10.1095/biolreprod33.2.495
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发表时间：
1985-09
影响因子：
3.6
通讯作者：
W. Maxson;A. Haney;D. W. Schomberg
中科院分区：
文献类型：
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作者：
W. Maxson;A. Haney;D. W. Schomberg
为了评估闭锁过程中猪卵泡液中雌激素浓度降低的机制，选择直径为4 - 7 mm的非闭锁和闭锁卵泡。卵泡液中雌激素浓度在闭锁卵泡中低7-16倍。与非闭锁卵泡的颗粒细胞相比，闭锁卵泡的颗粒细胞芳香化酶活性和促卵泡激素（FSH）诱导的孕酮分泌在体外显著降低。从闭锁卵泡分离卵泡膜也表现出雌激素的产生减少。然而，雄激素浓度是相等的闭锁和非闭锁卵泡的卵泡液中，和闭锁卵泡膜维持睾酮和雄烯二酮的生产在体外。闭锁时卵泡膜芳香化酶活性的丧失并不继发于FSH反应性的降低，因为FSH在体外并不增加卵泡膜孕酮的产生。细胞变性也不能解释卵泡膜雌激素产生的减少，因为体外雄激素输出和卵泡液雄激素浓度都保持不变。因此，这些数据表明，在闭锁的这个阶段，除了FSH反应性降低之外，还有一种机制必须解释卵泡膜芳香化酶活性的选择性丧失。
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.