Acute effects of captopril, an angiotensin-converting enzyme inhibitor, on the pregnant ewe and fetus.
After control measurements had been made, 15 chronically catheterized pregnant ewes (gestational age 123-141 days) were given 15 mg of captopril intravenously followed by an infusion of 6 mg/h. These doses blocked the pressor responses of both ewes and fetuses to 5 micrograms of angiotensin I. After captopril, maternal mean arterial pressure fell from 94 +/- 3.5 to 88 +/- 3.6 (SE) mmHg (P less than 0.0001) and pulse interval fell (P = 0.008). Maternal flow to the cotyledons fell from 766 +/- 118 to 525 +/- 77 ml/min (P = 0.002), as did flow to the remainder of the maternal placenta, i.e., the caruncles and their underlying myoendometrium (control flow 188 +/- 35 ml/min, flow 10-15 min after captopril 166 +/- 36.1 ml/min; P = 0.021). Flow to the rest of the myometrium did not change. Fetal arterial pressure fell from 46.9 +/- 1.6 to 44.1 +/- 1.6 mmHg (P less than 0.009), and fetal placental blood flow fell from 639.9 +/- 93.2 to 413.1 +/- 53.9 ml/min (P = 0.025). Flow to the fetal membranes declined also, from 53.2 +/- 6.5 to 35.6 +/- 3.3 ml/min (P less than 0.005). Maternal and fetal renal blood flows and fetal adrenal blood flows were unchanged. Fetal arterial PO2 was initially 19.5 +/- 0.8 mmHg; after captopril, it was 17.7 +/- 0.9 mmHg (P = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)
Lumbers
E R
ER
School of Physiology and Pharmacology, University of New South Wales, Kensington, Australia.
Kingsford
N M
NM
Menzies
R I
RI
Stevens
A D
AD
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D000818:Animals; D001158:Arteries; D001775:Blood Circulation / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology*; D002319:Cardiovascular System / Q000187:drug effects / Q000196:embryology; D005260:Female; D005333:Fetus / Q000187:drug effects* / Q000502:physiology; D005740:Gases / Q000097:blood; D006863:Hydrogen-Ion Concentration; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects* / Q000502:physiology; D012756:Sheep; D016216:Ultrasonography, Prenatal; D014655:Vascular Resistance / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D005740:Gases; D002216:Captopril