Pre-eclampsia does not alter the response to endothelin-1 in human omental artery

Endothelin-1 (ET-1), known to be present in high concentrations in serum from preeclamptic compared with normotensive pregnant women, may contribute to the increased vascular reactivity seen in pre-eclampsia. Experiments were designed to compare the contractile activity of ET-1 in isolated omental arteries from menopausal women (n = 6), normotensive pregnant women (n = 7), and pre-eclamptic patients (n = 7). Intact rings (3-mm width) were suspended for isometric tension recording in organ chambers filled with modified Krebs/bicarbonate buffer aerated with 95% air and 5% CO₂, 37°C, pH 7.35-7.4, under tension of 1 g. No significant differences were found in either the sensitivity to (concentration producing 50% of contraction) or efficacy of (maximal increase in tension, normalized to reference contraction to KC1) ET-1 in the vessels of all three groups of patients studied. These data argue against ET-1 as a primary factor in pre-eclampsia. The modulatory role of ET-1 on the effects of other contractile factors of human blood, as a possible cause of pre-eclamptic changes, remains to be elucidated.