ANGIOTENSIN-CONVERTING ENZYME-INHIBITORS HAVE NO EFFECT ON OVULATION AND OVARIAN STEROIDOGENESIS IN THE PERFUSED RAT OVARY

The null hypothesis of this study was that the angiotensin-converting enzyme inhibitors, captopril and teprotide, would not reduce the numbe r of ovulations in vivo and in vitro in the rat. Captopril (in three r egimens) was administered continuously beginning prior to pregnant mar e's serum gonadotropin and hCG to trigger ovulation. The number of in vivo ovulations were counted. Ovaries similarly primed with pregnant m are's serum gonadotropin were dissected and perfused in media with hCG and captopril (two regimens) or teprotide (one regimen). The number o f in vitro ovulations and steroid production in the perfusions were ev aluated. The results were evaluated by the Student's t test. Power cal culations gave only a 20% chance of missing a 16% difference in ovulat ions or steroidogenesis. There was no inhibition of ovulation or chang e in steroid production in angiotensin-converting enzyme treated rats in vivo or in vitro. While angiotensin II has been shown to be an impo rtant mediator in the mechanism of ovulation, angiotensin-converting e nzyme inhibition via captopril or teprotide does not result in angiote nsin II antagonistic effects. Hypothetical mechanisms to explain this paradox are presented.