17β-estradiol acutely improves endothelium-dependent relaxation to bradykinin in isolated human coronary arteries

Improvement of endothelial function has been implicated in the cardioprotective effects of estrogens in women. In isolated human coronary arteries, we investigated whether 17 beta-estradiol affects endothelium-dependent responses to bradykinin, an endothelium-derived vasodilator locally produced by endothelial cells. Concentration-response curves to bradykinin (0.03-300 nM) or nitroglycerine (0.01-1 mu M) were obtained before and after 30 min of incubation with 17 beta-estradiol (3 mu M) or solvent control (ethanol 0.2% vol/vol). Incubation with 17 beta-estradiol enhanced relaxations to bradykinin (from 43 +/- 6 to 83 +/- 3%, P < 0.0001) but not those to nitroglycerine (n.s.). Improvement of bradykinin-mediated endothelium-dependent relaxation may represent a novel mechanism contributing to the cardioprotective effects of estrogen in women. (C) 1998 Elsevier Science B.V. All rights reserved.