Activin from secondary follicles causes small preantral follicles to remain dormant at the resting stage
Activin from secondary follicles causes small preantral follicles to remain dormant at the resting stage
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DOI：
10.1210/en.140.1.37
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发表时间：
1999-01-01
期刊：
影响因子：
4.8
通讯作者：
Hasegawa, Y
中科院分区：
文献类型：
--
作者：
Mizunuma, H;Liu, XW;Hasegawa, Y
本研究的目的是探讨1)激活素A是否能使初生卵泡在静息期进入休眠状态，2)次生卵泡对初生卵泡生长的作用。在体外卵泡培养系统中培养的成年小鼠的卵泡（直径100-120 μ m）在FSK的作用下，卵泡的大小、雌激素和抑制素的分泌明显增加，但激活素a抑制了FSH的作用。停用激活素A不仅能恢复卵泡对FSH的反应，还能增强FSH的作用，说明激活素A的作用是使小的腔前卵泡在腔前阶段进入休眠状态。为了研究次生卵泡在早期卵泡形成中的作用，在FSH存在的情况下，将小的腔前卵泡与次生卵泡（直径300-350 μ m）共培养。由于FSH的刺激，次级卵泡的卵泡直径明显增加，但小的腔前卵泡的大小没有增加。然而，在去除次级卵泡后，小的腔前卵泡开始卵泡生长，这表明小的腔前卵泡的生长受到次级卵泡的抑制。激活素结合蛋白卵泡抑素（follistatin）的使用，由于FSH的刺激，导致小的腹前和次级卵泡直径显著增加。这些结果表明，次级卵泡通过分泌激活素使初级卵泡在休息阶段进入休眠状态。
The purpose of the present study was to investigate 1) whether activin A can cause primary follicles to become dormant at the resting stage, and 2) the role of the secondary follicle on follicular growth of primary follicles. Preantral follicles (100-120 mu m in diameter) harvested from adult mice and cultured in in vitro follicle culture system showed a significant increase in size and estrogen and inhibin secretion in response to FSK, but the administration of activin A blocked the effect of FSH. Withdrawal of activin A not only restored the follicular response to FSH but also enhanced the effect of FSH, indicating that the action of activin A is to cause small preantral follicles to become dormant at the preantral stage. To investigate the role of secondary follicles in early folliculogenesis, small preantral follicles were cocultured with secondary follicle (300-350 mu m in diameter) in the presence of FSH. The secondary follicle showed a significant increase in follicular diameter as a result of stimulation by FSH, but the small preantral follicles did not increase in size. After removal of the secondary follicle, however, the small preantral follicles commenced follicular growth, indicating that the growth of small preantral follicles is suppressed by the secondary follicle. Administration of the activin binding protein follistatin caused a significant increase in follicular diameter of both small preantral and secondary follicles as a result of stimulation by FSH. These results have suggested that secondary follicles cause primary follicles to become dormant at the resting stage by secreting activin.