Effects of prostaglandins E1, E2, and F2alpha on uterine blood flow in nonpregnant sheep.

The effects of prostaglandins E1, E2, and F2alpha (PGE1, PGE2, and PGE2alpha, respectively) on uterine blood flow were investigated in chronically catheterized, nonpregnant sheep equipped with electromagnetic flow probes. PGE1 was found to be a potent dilator of the uterine vascular bed and, at initial arterial concentratios of 1.5 micron (500 ng/ml), produced peak uterine blood flows similar to those achieved by a pulsed dose of 1 microgram 17beta-estradiol; PGE2 had less active vasodilating activity. Conversely, uterine intra-arterial PGF2alpha infusions, which produced initial concentrations of 0.1 micron (50 ng/ml), promptly reduced peak estrogen-stimulated uterine blood flow by 60%. All prostaglandin infusions stimulated increases in uterine contractile frequency and base-line tone. The findings demonstrate the sensitivity of the nonpregnant sheep uterine vasculature to prostaglandins.