EFFECTS OF INDOMETHACIN ON THE SELECTIVE RELEASE OF FOLLICLE-STIMULATING-HORMONE DURING THE PERIOD OF OVULATION IN THE RAT

To determine whether indomethacin, a potent inhibitor of prostaglandin s endoperoxide synthetase, affects the selective follicle-stimulating hormone (FSH) surge during the period of ovulation, the compound was a dministered intravenously (iv), concurrent with 10 IU human chorionic gonadotropin (hCG), to diestrous female rats at 16:00 hr. Indomethacin inhibited the number of ovulations in a dose-dependent manner, and tr eatment with 500 mu g indomethacin reduced number of oocytes in the am pullae most effectively without enteric lesions. In the histological o bservation, oocytes that had began to mature were found not only in un ruptured luteinized follicles but also in ovarian interstitium beneath ruptured luteinized follicle. Despite the inhibitory effects of indom ethacin on ovulation, peri-ovulatory FSH and progesterone surges occur red in comparable levels and duration to vehicle-treated animals. Thes e results indicate that indomethacin-induced inhibition of prostagland in synthesis does not affect the selective release of FSH during the p eri-ovulatory period.