Kwon H B, Schuetz A W
J Exp Zool. 1985 Nov;236(2):219-28. doi: 10.1002/jez.1402360212.
The role of cyclic AMP (cAMP) in ovarian follicular functions in Rana pipiens was investigated with the use of the adenylate cyclase stimulator, forskolin, which is thought to elevate intracellular level of cAMP. Effects of forskolin on oocyte germinal vesicle breakdown (GVBD) and on progesterone production by the follicles were assessed during the course of in vitro culture. Addition of forskolin to culture medium suppressed both progesterone-and frog pituitary homogenate (FPH)-induced meiotic maturation of the oocytes. Inhibitory effects of forskolin were essentially reversible and forskolin completely inhibited GVBD when added during the first four hours of incubation following exposure to progesterone. Forskolin alone stimulated a low level progesterone production by isolated follicles, but markedly stimulated progesterone production when it was supplemented with a low dose of FPH (0.005 pituitary equivalent/ml). Thus, forskolin acts synergistically with FPH on follicle cells to stimulate progesterone production. A higher dose of FPH (0.05 pitui. eq./ml) produced no additional synergistic effect of forskolin. Therefore, forskolin appears to have two contradictory functions in ovarian follicles: it augments FPH induced follicle secretion of meiosis initiator, progesterone, and simultaneously suppresses the maturation of the oocytes triggered by exogenous progesterone or FPH. The data presented indicate that there are two independent adenylate cyclase systems in the ovarian follicles which have separate functions: one in the follicle cells and the other in the oocyte. The two enzyme systems are thus compartmentalized and regulate different biological functions using the same messenger, cAMP. The data provide evidence that in amphibians, as in mammals, pituitary hormones regulate steroid hormone production by follicle cells via a cyclic AMP system. Thus, control of oocyte maturation induction appears to be determined by the relative levels of cAMP present in the follicle cells and oocytes.
利用腺苷酸环化酶刺激剂福斯高林研究了环磷酸腺苷（cAMP）在牛蛙卵巢卵泡功能中的作用，福斯高林被认为可提高细胞内cAMP水平。在体外培养过程中，评估了福斯高林对卵母细胞生发泡破裂（GVBD）和卵泡孕酮分泌的影响。向培养基中添加福斯高林可抑制孕酮和蛙垂体匀浆（FPH）诱导的卵母细胞减数分裂成熟。福斯高林的抑制作用基本可逆，在暴露于孕酮后的孵育前四小时内添加福斯高林可完全抑制GVBD。单独使用福斯高林可刺激分离的卵泡产生低水平的孕酮，但在添加低剂量FPH（0.005垂体当量/毫升）时可显著刺激孕酮分泌。因此，福斯高林与FPH在卵泡细胞上协同作用以刺激孕酮分泌。更高剂量的FPH（0.05垂体当量/毫升）未产生福斯高林的额外协同作用。因此，福斯高林在卵巢卵泡中似乎具有两种相互矛盾的功能：它增强FPH诱导的卵泡减数分裂启动子孕酮的分泌，同时抑制外源性孕酮或FPH触发的卵母细胞成熟。所呈现的数据表明，卵巢卵泡中有两个独立的腺苷酸环化酶系统，具有不同的功能：一个在卵泡细胞中，另一个在卵母细胞中。因此，这两个酶系统是分隔的，并使用相同的信使cAMP调节不同的生物学功能。这些数据提供了证据，表明在两栖动物中，与哺乳动物一样，垂体激素通过环磷酸腺苷系统调节卵泡细胞的类固醇激素分泌。因此，卵母细胞成熟诱导的控制似乎取决于卵泡细胞和卵母细胞中cAMP的相对水平。
