The effect of 17 beta-estradiol on isolated omental arteries from preeclamptic women

Objective: To study the effect of 17 beta -estradiol on isolated omental ar teries from preeclamptic women. Study Design: Rings of omental artery with intact endothelium were mounted iu organ chambers for isometric tension rec ording. We studied the effect of pharmacological concentrations of 17 beta -estradiol on potassium chloride-induced tension and the concentration-cont raction relationships for norepinephrine and calcium. Results: Cumulative a pplication of 17 beta -estradiol, in a concentration-dependent manner, rela xed potassium chloride contracted rings. Sixty minutes of incubation with 1 7 beta -estradiol (10(-5) mol/l) attenuated the tension developed in respon se to potassium chloride, norepinephrine and calcium. Tamoxifen (10(-6) mol /l) did not antagonize the inhibitory actions of 17 beta -estradiol. Conclu sions: Pharmacological concentrations of 17 beta -estradiol retain the capa bility for relaxing omental artery rings from preeclamptic women. The loss of refractoriness to norepinephrine, increased responsiveness to calcium io ns and decreased ability of 17 beta -estradiol to inhibit calcium-induced t ension may be responsible for increased vascular reactivity in preeclampsia . (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.