Acute administration of 17β-estradiol improves endothelium-dependent vasodilation in postmenopausal women

Objectives: Estrogen's effect on endothelial function in postmenopausal women with mild hypertension but no other cardiovascular risk factors remains unclear. This study investigated the effect of an acutely administered therapeutic/low dose of 17β-estradiol on vasodilation in this patient population. Methods: Forearm blood flow (FBF) was measured in seven white, hypertensive (blood pressure 144 ± 8/93 ± 5 mmHg), postmenopausal (mean age: 54.4 ± 5 years) women at baseline and during the intra-brachial infusion of increasing doses of acetylcholine (ACh; 0.75, 5, and 15 μg/100 mL tissue/min) and sodium nitroprusside (NP; 1, 2, and 4 μg/100 mL tissue/min). These measurements were obtained both before and after the sublingual administration of 17β-estradiol. Eight normotensive women (blood pressure 115 ± 8/76 ± 5 mmHg) with otherwise similar characteristics served as controls (mean age: 55.8 ± 5 years). Exclusion criteria included medications or any condition that could alter endothelial function. Results: Before estradiol administration, FBF values at baseline and after all doses of ACh and NP were similar between groups. Acutely administered 17β-estradiol significantly improved the FBF response to ACh in both the normotensive (maximal response: 17.6 ± 5 versus 22.5 ± 7 mL/min/100 mL) and hypertensive (11 ± 4 versus 16 ± 6; 12 ± 4 versus 17 ± 5 and 14 ± 3 versus 20 ± 7 mL/min/100 mL) groups. It also altered the NP dose-response curve in the both groups. Conclusion: 17β-estradiol improved vasodilatory responses in mildly hypertensive postmenopausal women without other risk factors for cardiovascular disease.