LH-Stimulable Adenylyl Cyclase Activity During the Ovulatory Cycle in Granulosa Cells of the Three Largest Follicles and the Postovulatory Follicle of the Domestic Hen (Gallus domesticus)

Abstract

The adenylyl cyclase (AC) activity in the granulosa (Gr) cells of the largest (F₁), next largest (F₂), third largest (F₃), and postovulatory (POF) follicles throughout the ovulatory cycle of the domestic hen was measured. Granulosa cells were isolated at 24, 18, 12, 8, 6, 4, and 2 h before ovulation and basal and LH-stimulable AC activities were determined. There was a significant difference (P1 Gr at all times studied, with the most dramatic difference observed between 18 and 12 h before ovulation (P< 0.001) (18 h, 58.42 ± 4.72 vs 12 h, 105.13 ± 4.89 pmoles cAMP/min/mg protein). There was a transient decrease in basal and LH-stimulable AC activities after the LH surge, followed by a significant (P2 Gr cells were essentially the same as those of the F₁ Gr except that the relative LH stimulation was less. In contrast, the pattern of AC activity of the F₃ Gr cells differed from that of the F₁ and F₂ follicles. At all times assayed except 6 and 4 h before ovulation, the LH-stimulable activity was significantly greater (P<0.05) than basal values, which remained the same throughout the cycle. The LH-stimulable AC activity of the Gr cells of the POF was still significantly (P<0.001) elevated 2 h after ovulation, but declined to basal levels 4 h later. There was a significant increase in the basal AC activity of the POF at 24 h after ovulation.