Effect of gender on NADPH-oxidase activity, expression, and function in the cerebral circulation: role of estrogen.
OBJECTIVE
This study tested whether NADPH-oxidase activity, expression, and functional effects on vascular tone are influenced by gender in the rat cerebral circulation and whether such differences are estrogen-dependent.


METHODS
NADPH-stimulated superoxide production by cerebral (basilar [BA]; middle cerebral) arteries from male and female Sprague-Dawley rats was measured using lucigenin-enhanced chemiluminescence and dihydroethidium. Protein expression of Nox1, Nox2, Nox4, superoxide dismutase 1 (SOD1), SOD2, and SOD3 was measured using Western blotting. Vascular responses of BA to NADPH were assessed in a myograph. Some female rats were ovariectomized and treated with either vehicle (dimethyl sulfoxide) or 17beta-estradiol.


RESULTS
NADPH-stimulated superoxide production by BA and middle cerebral arteries from males was approximately 2-fold greater than vessels from females. Superoxide production was virtually abolished by the NADPH-oxidase inhibitor, diphenyleneiodonium. Protein expression of Nox1 and Nox4 in BA was also higher in males than in females (2.4- and 2.8-fold, respectively), whereas Nox2, SOD1, SOD2, and SOD3 expression did not differ between genders. NADPH induced greater vasorelaxant effects in BA from males versus females (P<0.05). The hydrogen peroxide scavenger, catalase, abolished these NADPH-induced relaxations. NADPH-stimulated superoxide production by BA from ovariectomized rats treated with vehicle was 3-fold greater than levels in intact females. Treatment of ovariectomized rats with 17beta-estradiol decreased superoxide production (P<0.05). NADPH-induced relaxations of BA were smaller in 17beta-estradiol-treated than in vehicle-treated ovariectomized rats (P<0.05).


CONCLUSIONS
NADPH-oxidase activity and function are lower in cerebral arteries of female rats. These gender differences are estrogen-dependent and are associated with lower Nox1 and Nox4 expression.
Miller
Alyson A
AA
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Drummond
Grant R
GR
Mast
Anja E
AE
Schmidt
Harald H H W
HH
Sobey
Christopher G
CG
D000818:Animals; D001488:Basilar Artery / Q000033:anatomy & histology / Q000378:metabolism; D002536:Cerebral Arteries / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D004967:Estrogens / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D006861:Hydrogen Peroxide / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D008297:Male; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D010052:Ovariectomy; D016877:Oxidants / Q000378:metabolism; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014664:Vasodilation / Q000502:physiology
D004967:Estrogens; D007527:Isoenzymes; D016877:Oxidants; D021122:Protein Subunits; D013481:Superoxides; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D019255:NADPH Oxidases