Sakairi Kazuhiro, Shirai Hiroko
Ushimado Marine Laboratory, Okayama University, Kashino, Ushimado, Oku, Okayama 701-43, Japan.
Dev Growth Differ. 1991 Apr;33(2):155-162. doi: 10.1111/j.1440-169X.1991.00155.x.
Outer and inner follicle cell-enclosed oocytes (oocyte complexes) of Halocynthia roretzi underwent germinal vesicle breakdown (GVBD) within 2 hr when transferred from ovaries to normal seawater of pH 8 (NSW). Extrusion of test cells (TC) into the perivitelline space and elevation of the chorion also occurred. This phenomenon was designated as spontaneous oocyte maturation. Seawater of low pH, protease inhibitors such as leupeptin or soybean trypsin inhibitor (SBTI), and calcium deficiency inhibited the spontaneous maturation only when introduced to the NSW during the first 10 minutes of incubation. GVBD-blocked complexes underwent GVBD after addition of trypsin regardless of pH or the absence of calcium ions. The oocytes from which follicle cells were removed with glycosidase did not undergo GVBD in NSW, but addition of trypsin triggered GVBD in these defolliculated oocytes (TC oocytes). Furthermore, incubation media in which spontaneous maturation had occurred, induced GVBD in the TC oocytes. This GVBD-inducing activity was heat-labile and was inhibited by leupeptin. These results indicate that in the first step of the spontaneous oocyte maturation, outer and/or inner follicle cells give a signal to the oocyte itself or TC oocyte. This signal is likely to be trypsin-like.
将柄海鞘的外层和内层卵泡细胞包裹的卵母细胞（卵母细胞复合体）从卵巢转移至pH 8的正常海水（NSW）中后，2小时内会发生生发泡破裂（GVBD）。也会出现测试细胞（TC）挤入卵周隙以及卵膜隆起的现象。这种现象被称为自发卵母细胞成熟。低pH海水、蛋白酶抑制剂如亮抑蛋白酶肽或大豆胰蛋白酶抑制剂（SBTI）以及钙缺乏仅在孵育的前10分钟内引入NSW时才会抑制自发成熟。无论pH值如何或是否存在钙离子，添加胰蛋白酶后，GVBD阻断的复合体都会发生GVBD。用糖苷酶去除卵泡细胞的卵母细胞在NSW中不会发生GVBD，但添加胰蛋白酶会在这些去卵泡卵母细胞（TC卵母细胞）中引发GVBD。此外，已发生自发成熟的孵育培养基会诱导TC卵母细胞发生GVBD。这种GVBD诱导活性对热不稳定，并被亮抑蛋白酶肽抑制。这些结果表明，在自发卵母细胞成熟的第一步中，外层和/或内层卵泡细胞会向卵母细胞自身或TC卵母细胞发出信号。这个信号可能类似于胰蛋白酶。
