17 beta-Estradiol induces a rapid, endothelium-dependent, sex-specific vasodilatation in spontaneous constricted rat arterioles.

Objective: Our purpose was to resolve the apparent contradiction between the endothelium-dependent and endothelium-independent vasodilator effects of 17 beta-estradiol reported in different studies.

Study Design: The inner diameters of isolated pressurized spontaneously constricted muscle arterioles (diameter = 63 microm) from Wistar rats (n = 21) were measured during exposure to 17 beta-estradiol, and the role of the endothelium and the influence of sex were assessed.

Results: A dose-dependent dilatation was observed during exposure to 17 beta-estradiol concentrations from 10(-10) to 10(-4) mol/L.