title: Nongenomic responses to 17beta-estradiol in male rat mesenteric arteries abolish intrinsic gender differences in vascular responses.
abstract: The aim of the present study was to investigate the gender differences in the acute effects of 17beta-estradiol on the rat superior mesenteric artery. Isometric tension was measured in rings of mesenteric arteries from both male and female Sprague-Dawley rats. Relaxation to acetylcholine was not significantly different between arteries (with endothelium) from male and female rats in the absence or presence of 17beta-estradiol. After blockade of endothelium-dependent hyperpolarizations with apamin (0.3 microM) plus charybdotoxin (0.1 microM), acute exposure to 17beta-estradiol (1 nM) for 30 min resulted in enhancement of relaxation to acetylcholine in arteries from male but not female rats. After acute exposure to 17beta-estradiol, mesenteric arteries from male rats were more sensitive to sodium nitroprusside than arteries from female rats. Contractions of mesenteric arteries to phenylephrine and 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F(2alpha) (U46619) were greater in arteries from male rats than female rats. This difference was not detected after acute exposure to 17beta-estradiol. In preparations without endothelium, the enhancement of relaxation and reduction in contraction in arteries from male rats were preserved. These results suggest that there exists a gender difference in the response to the acute nongenomic modulatory effect of 17beta-estradiol in rat mesenteric arteries. Arteries from male rats seem to be more sensitive to the modulatory effects of 17beta-estradiol than arteries from female rats. The effect appears to be mainly at the level of the vascular smooth muscles.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, The University of Hong Kong, Level 2, Laboratory Block, Faculty of Medicine Building, 21 Sassoon Road, Hong Kong SAR, People's Republic of China.
authors.forename: Wendy
authors.initials: W
authors.lastname: Keung
authors.forename: Paul M
authors.initials: PM
authors.lastname: Vanhoutte
authors.forename: Ricky Y K
authors.initials: RY
authors.lastname: Man
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects*; D017538:Mesenteric Artery, Superior / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D010656:Phenylephrine; D004958:Estradiol; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D000109:Acetylcholine