Hemodynamic effects of leukotriene C4 in ovine fetus.
Leukotrienes are synthesized during pregnancy and produce cardiovascular effects in adults. We hypothesized that leukotriene C4 would cause vasoconstriction in the fetus and placenta. Eight near-term, unanesthetized ovine fetuses were studied before and after infusion of 10 micrograms leukotriene C4 (LTC4) into the fetal vena cava. Cardiovascular monitoring of maternal and fetal arterial pressures and heart rates was performed. Fetal blood flows were measured by the radioactive-microsphere technique. Sustained elevations in systolic and diastolic blood pressure and decreased fetal heart rate began by 1 min and returned to baseline by 30 min. Arterial pH fell from 7.33 +/- 0.01 to 7.29 +/- 0.01 at 15 min (P less than 0.05) and to 7.29 +/- 0.01 at 30 min (P less than 0.05), with a significant increase in base deficit from 0.7 +/- 0.7 to 3.5 +/- 0.7 at 15 min (P less than 0.05) and to 2.9 +/- 1.0 at 30 min (P less than 0.05). Fetal PO2 and PCO2 were unchanged. Significant decreases in blood flow and resistance were seen in the umbilical placental circulation as well as in fetal skeletal muscle and intestine. Blood flow and resistance were unchanged in the renal and adrenal vascular beds. Fetal administration of LTC4 caused no changes in maternal cardiovascular parameters. These findings represent the first in vivo studies of the effects of a lipoxygenase metabolite on fetal-placental blood flow.
Meyer
B A
BA
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Medical School, Houston 77030.
Walsh
S W
SW
Parisi
V M
VM
D000818:Animals; D001639:Bicarbonates / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005333:Fetus / Q000187:drug effects / Q000502:physiology*; D006340:Heart Rate, Fetal / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007422:Intestines / Q000098:blood supply; D009132:Muscles / Q000098:blood supply; D010100:Oxygen / Q000097:blood; D010920:Placenta / Q000098:blood supply; D011247:Pregnancy; D012016:Reference Values; D012039:Regional Blood Flow / Q000187:drug effects; D013189:SRS-A / Q000494:pharmacology*; D012756:Sheep; D014655:Vascular Resistance / Q000187:drug effects
D001639:Bicarbonates; D013189:SRS-A; D002245:Carbon Dioxide; D010100:Oxygen