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 number of ovulations in vivo and in vitro in the rat. Captopril (in three regimens) was administered continuously beginning prior to pregnant mare's serum gonadotropin and hCG to trigger ovulation. The number of in vivo ovulations were counted. Ovaries similarly primed with pregnant mare's serum gonadotropin were dissected and perfused in media with hCG and captopril (two regimens) or teprotide (one regimen). The number of in vitro ovulations and steroid production in the perfusions were evaluated. The results were evaluated by the Student's t test. Power calculations gave only a 20% chance of missing a 16% difference in ovulations or steroidogenesis. There was no inhibition of ovulation or change in steroid production in angiotensin-converting enzyme treated rats in vivo or in vitro. While angiotensin II has been shown to be an important mediator in the mechanism of ovulation, angiotensin-converting enzyme inhibition via captopril or teprotide does not result in angiotensin II antagonistic effects. Hypothetical mechanisms to explain this paradox are presented.
Department of Obstetrics and Gynecology, University of Utah, Salt Lake City.
C M
CM
Peterson
N
N
Morioka
C
C
Zhu
J W
JW
Ryan
W J
WJ
LeMaire
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000633:toxicity*; D000818:Animals; D002216:Captopril / Q000633:toxicity; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D010053:Ovary / Q000187:drug effects / Q000378:metabolism*; D010060:Ovulation / Q000187:drug effects*; D010477:Perfusion; D011374:Progesterone / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013256:Steroids / Q000096:biosynthesis*; D013722:Teprotide / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D013256:Steroids; D011374:Progesterone; D004958:Estradiol; D002216:Captopril; D013722:Teprotide