EFFECTS OF ESTRADIOL-17-BETA AND PROGESTERONE ON ISOLATED HUMAN OMENTAL ARTERY FROM PREMENOPAUSAL NONPREGNANT WOMEN AND FROM NORMOTENSIVE AND PREECLAMPTIC PREGNANT-WOMEN

OBJECTIVE: Our purpose was to study the direct vascular effects of est radiol-17 beta and progesterone on isolated omental artery from premen opausal nonpregnant women and from normotensive and preeclamptic pregn ant women. STUDY DESIGN: Omental artery rings from normotensive premen opausal nonpregnant women and from normal and preeclamptic pregnant wo men were mounted in Krebs-bicarbonate solution in organ baths for isom etric tension recording. The endothelium was removed from some of the rings, and all were contracted with potassium chloride (60 mmol/L) and then exposed to cumulative concentrations of estradiol-17 beta and pr ogesterone. Concentration response curves were constructed and relaxat ion was expressed as percent change from the reference 60 mmol/L potas sium chloride contraction. Data analysis was by repeated-measures anal ysis of variance, Newman-Keuls test, and the unpaired Student t test a s appropriate. A two-tailed p < 0.05 was considered statistically sign ificant. RESULTS: Both hormones studied caused vasorelaxation in oment al arteries from all three groups of patients. Of the two, estradiol-1 7 beta was more effective, regardless of the presence or absence of en dothelium. Removal of the endothelium shifted the estradiol-17 beta co ncentration-response curve to the right in the normal pregnant artery but not in nonpregnant or preeclamptic vessels. Removal of the endothe lium shifted the progesterone concentration-response curve to the left in arteries from preeclamptic patients. CONCLUSIONS: Estradiol-17 bet a and progesterone have direct in vitro vasodilator activity that appe ars to be linked, in part, to the endothelium in human omental artery from normal and hypertensive women in different hormonal states.