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 O-2(-) (about 34%) than the aortae from female animals. Removal of endothelium reduced generation of O-2(-) in the aorta of male and female rats by 23.9 +/- 1.3 and 15.3 +/- 2.3 pmole O-2(-) min(-1) mg(-1) dry weight (p<0.05), respectively. The denuded aortae of both sexes showed no different O-2(-) production. Generation of O-2(-) could not be influenced by inhibition of cycloxygenase with indomethacin or xanthine oxidase with oxypurinol. In contrast to the generation of O-2(-) under basal conditions, stimulated generation of O-2(-) 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 O-2(-) under basal conditions than the endothelium from female rats.