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

• Published in: American journal of obstetrics and gynecology Vol. 187; no. 2; pp. 375 - 381
• Main Authors: Smolders, Ramon G.V., van der Mooren, Marius J., Kenemans, Peter, van der Linden, Peter W.J., Stehouwer, Coen D.A., Sipkema, Pieter
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Mosby, Inc 01.08.2002; Elsevier
• Subjects: Biological and medical sciences; Blood vessels and receptors; endothelium; Estradiol; Fundamental and applied biological sciences. Psychology; rat; spontaneous constriction; vasodilatation; Vertebrates: cardiovascular system; vasodilatation; endothelium; spontaneous constriction; rat; Estradiol; Rat; Enzyme; Arteriole; Estrogen; Rodentia; Sex; Vasoconstriction; 17β-Estradiol; Enzyme inhibitor; Experimental study; Ovarian hormone; Biological activity; Nitric-oxide synthase; Vasodilation; Vertebrata; Mammalia; Animal; Hormonal regulation; Oxidoreductases; Sex steroid hormone
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1067/mob.2002.123599

Objective: Our purpose was to resolve the apparent contradiction between the endothelium-dependent and endothelium-independent vasodilator effects of 17β-estradiol reported in different studies. Study Design: The inner diameters of isolated pressurized spontaneously constricted muscle arterioles (diameter = 63 μm) from Wistar rats (n = 21) were measured during exposure to 17β-estradiol, and the role of the endothelium and the influence of sex were assessed. Results: A dose-dependent dilatation was observed during exposure to 17β-estradiol concentrations from 10−10 to 10−4 mol/L. Arterioles of female rats displayed significantly more dilatation than vessels from male rats. The dilatation was significantly less in endothelium-denuded arterioles or after pretreatment with and in the presence of a nitric oxide synthase inhibitor. Conclusions: These results provide strong evidence that, in addition to an endothelium-independent effect, 17β-estradiol has a dose-dependent, endothelium-mediated, rapid vasodilatory effect on muscle arterioles from the rat, which is stronger in female rats than in male rats. (Am J Obstet Gynecol 2002;187:375-81.)