Gender differences in the generation of superoxide anions in the rat aorta

Generation of superoxide anions was measured in the isolated aorta of female and male rats using a lucigenin chemiluminescence technique. Aortae from male rats produced significantly more O2- (about 34%) than the aortae from female animals. Removal of endothelium reduced generation of O2- in the aorta of male and female rats by 23.9 +/- 1.3 and 15.3 +/- 2.3 pmole O2- min-1 mg-1 dry weight (p < 0.05), respectively. The denuded aortae of both sexes showed no different O2- production. Generation of O2- could not be influenced by inhibition of cycloxygenase with indomethacin or xanthine oxidase with oxypurinol. In contrast to the generation of O2- under basal conditions, stimulated generation of O2- by either addition of phorbol 12-myristate 13-acetate (to stimulate protein kinase C) or diethylthiocarbamate (to inhibit vascular superoxide dismutase activity) showed no significant gender differences. It is concluded that the endothelium from male rats produces more O2- under basal conditions than the endothelium from female rats.