Effects of two low-dose oral contraceptives on erythrocyte superoxide dismutase, catalase and glutathione peroxidase activities.

The effect of a triphasic combination of ethinyl estradiol and levonorgestrel upon activities of superoxide dismutase, catalase and glutathione peroxidase in erythrocytes was compared to that of a preparation that contained ethinyl estradiol and desogestrel on the 21st day of a control cycle, of the third cycle of treatment with ethinyl estradiol/levonorgestrel or ethinyl estradiol/desogestrel (14 volunteers each), and of the third cycle of a 3-month washout period. Significant decreases were found in the activities of superoxide dismutase, catalase and glutathione peroxidase in erythrocytes with both preparations. The effect of desogestrel on the activities of the superoxide dismutase, catalase and glutathione peroxidase is similar to that of levonorgestrel. These data suggest that low-dose oral contraceptives, by decreasing the activities of antioxidant enzymes and by enhancing the lipid peroxidation, increase the risk of cardiovascular disease.