Follicular fluid depression of ovarian granulosa cell adenylyl cyclase activity

Previous studies have demonstrated that fluid from small (1--2 mm) porcine follicles is inhibitory of LH stimulation of cyclic AMP accumulation, progesterone secretion and morphological luteinization of granulosa cells from large (6--12 mm) porcine follicles. The present study measured adenylyl cyclase in granulosa cells following 2-day incubations in either the inhibitory culture medium containing 50% fluid from small follicles or in luteinization permissive media: 50% fluid from large follicles or 50% porcine serum. Basal, LH, epinephrine and NaF stimulation of adenylyl cyclase activity were all significantly reduced in the cells incubated with fluid from small follicles as compared to cells incubated in the control media. The data presented in this paper, in conjunction with previously publised data suggest that the inhibitory fluid from small follicles, alters both receptor--cyclase coordination and adenylyl cyclase activity.