INFLUENCE OF A STABLE PROSTACYCLIN ANALOG (ILOPROST) AND CYCLOOXYGENASE INHIBITION ON ANGIOTENSIN-II IN THE PERFUSED HUMAN-PLACENTA

  • 1 October 1989
    • journal article
    • research article
    • Vol. 66  (1) , 21-32
Abstract
Studies were undertaken on perfused human placentas to examine the effect of a stable prostacyclin analogue (iloprost) on the angiotensin-II (A-II) response in the placental vessels, and to examine how this response is influenced by cyclooxygenase inhibition. Iloprost, in doses of 1, 5, and 10 .mu.g significantly reduced the response of 50 .mu.g of A-II. The vasoconstriction produced by the autocoid was attenuated by the three doses of iloprost by 43.9.+-.5.2%, 56.5.+-.6.1%, and 39.7.+-.6.0%, respectively (MEAN .+-. S.E.). The 1 .mu.g dose of the analogue did not differ significantly from either the 5 .mu.g or 10 .mu.g dose in this regard. A 5 mg dose of the cyclooxygenase inhibitor indomethacin, when combined with 1 .mu.g of iloprost, also significantly attenuated the A-II response, although the dilating effects of iloprost was significantly reduced by indomethacin. This response of the autocoid was significantly reduced when compared to the A-II response preceded by only iloprost. Because the effects of A-II were attenuated by indomethacin, it is suggested that part of the mechanism of A-II is due to prostaglanding release into the placental circulation, the majority of which appear to have a pressor effect on the placental vessels.