AJP - Endocrinology and Metabolism, Vol 259, Issue 6 E851-E855, Copyright © 1990 by American Physiological Society
Hemodynamic effects of leukotriene C4 in ovine fetus
B. A. Meyer, S. W. Walsh and V. M. Parisi
Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Medical School, Houston 77030.
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.
