Abstract
Uterine renin may regulate uteroplacental blood flow locally through changes in vascular resistance or systemically by supporting arterial blood pressure. Captopril (5 mg/kg) was given i.v. to 14 conscious pregnant rabbits at day 27.5 +/- 0.3 of gestation for the purpose of investigating the effects of angiotensin converting enzyme inhibition on uteroplacental blood flow and oxygen consumption. Control measurements (mean +/- S.E.M.) were compared to measurements made at 1 hr (n = 14) and at 3 to 4 hr (n = 7). Arterial blood pressure decreased from 80 +/- 3 to 66 +/- 3 mm Hg, P less than .01, and then declined further to 56 +/- 4 mm Hg, P less than .01. Cardiac output was unchanged at 1 hr, 799 +/- 79 vs. 705 +/- 61 ml/min, but was decreased to 634 +/- 29 ml/min by 3 to 4 hr, P less than .01. There was no change in renal blood flow from 102 +/- 13 ml/min. Total uterine blood flow decreased from 37 +/- 5 to 29 +/- 5 ml/min, P less than .01, and then to 23 +/- 1 ml/min, P less than .01, whereas placental blood flow decreased from 25 +/- 4 to 19 +/- 3 to 15 +/- 3 ml/min, P less than .01; there was no significant change in myoendometrial flow. Oxygen delivery per uterine horn decreased from 2.4 +/- 0.3 to 1.8 +/- 0.4 to 1.6 +/- 0.2 ml/min, P less than .005. Oxygen consumption per horn decreased from 1.31 +/- 0.14 to 1.05 +/- 0.15 ml/min by 1 hr, P less than .05, and there was no further decrease.(ABSTRACT TRUNCATED AT 250 WORDS)
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