Lessman C A, Schuetz A W
Am J Physiol. 1981 Jul;241(1):E51-6. doi: 10.1152/ajpendo.1981.241.1.E51.
The involvement of the ovarian follicle wall in insulin induction of Rana pipiens oocyte maturation in vitro was examined. Complete removal of the follicle wall significantly decreased, but did not obliterate, oocyte maturation (i.e., germinal vesicle breakdown, GVBD) induced by insulin. Dose-response studies of GVBD induction revealed that oocytes within intact follicles were at least 100 times more sensitive to insulin than denuded oocytes. Addition of cyanoketone, a steroid biosynthesis inhibitor, to intact follicles also suppressed insulin-induced GVBD. Inhibitory effects of either follicle wall removal or cyanoketone were not observed when denuded oocytes were treated with progesterone. Addition of either progesterone or pregnenolone to insulin-treated denuded oocytes augmented the oocyte GVBD response compared to either steroid alone and essentially replaced the effect of the follicle wall. In summary, steroidogenesis in the follicle wall appears to be a major factor contributing to the ability of insulin to induce GVBD. However, whether insulin stimulates follicle wall steroidogenesis or simply augments the biological activity of endogenous basal steroid levels is unresolved. The in vitro results show that oocyte maturation can be modulated by the combined actions of several hormones. Such steroid-insulin interactions may also be relevant to understanding the control of oocyte maturation in amphibians and other vertebrates, including mammals, under physiological conditions in vivo.
研究了卵巢卵泡壁在体外胰岛素诱导豹蛙卵母细胞成熟过程中的作用。完全去除卵泡壁显著降低了胰岛素诱导的卵母细胞成熟（即生发泡破裂，GVBD），但并未使其完全消失。GVBD诱导的剂量反应研究表明，完整卵泡内的卵母细胞对胰岛素的敏感性至少是去卵丘卵母细胞的100倍。向完整卵泡中添加类固醇生物合成抑制剂氰酮也可抑制胰岛素诱导的GVBD。用孕酮处理去卵丘卵母细胞时，未观察到去除卵泡壁或氰酮的抑制作用。与单独使用任何一种类固醇相比，向胰岛素处理的去卵丘卵母细胞中添加孕酮或孕烯醇酮均可增强卵母细胞的GVBD反应，并且基本上取代了卵泡壁的作用。总之，卵泡壁中的类固醇生成似乎是胰岛素诱导GVBD能力的主要因素。然而，胰岛素是刺激卵泡壁类固醇生成还是仅仅增强内源性基础类固醇水平的生物活性仍未解决。体外实验结果表明，卵母细胞成熟可受多种激素的联合作用调节。这种类固醇-胰岛素相互作用可能也与理解两栖动物和包括哺乳动物在内的其他脊椎动物在体内生理条件下卵母细胞成熟的控制有关。
