Changes in progesterone production in granulosa cells during the ovulatory cycle of the Japanese quail (Coturnix coturnix japonica).

The influence of follicular maturation on progesterone production by isolated granulosa cells of the Japanese quail was examined. After determination of the concentrations of ovine LH (oLH) and dibutyryl cyclic AMP for the maximum response, the amount of progesterone produced during incubation at 40 degrees for 3 hr with or without oLH or dibutyryl cyclic AMP was measured in granulosa cells isolated from follicles at 71 to 1 hr before ovulation. When cells were stimulated with oLH, we found a marked increase in responsiveness between 23 and 21 hr before ovulation. The degree of responsiveness of cells obtained prior to this period was far less than that of cells of the latter period. The amount of progesterone produced by oLH increased between 21 and 17 hr before ovulation, followed by a transient decrease. Maximum responsiveness to oLH was obtained at 5 hr before ovulation. The changes in responsiveness of cells to dibutyryl cyclic AMP were essentially the same as those to oLH.