The effect of prolonged oral contraceptive steroid use on erythrocyte glutathione peroxidase activity

Abstract

Women using oral contraceptives have higher erythrocyte glutathione peroxidase levels than either pre-menopausal or post-menopausal non-oral contraceptive users. The levels of this enzyme were highest in the subjects who had been using these contraceptives for the longest periods of time. The increased enzyme levels were not the result of increased selenium or pyridoxal levels since there was no significant difference between the trace element and vitamin levels in contraceptive users and non-users. Subjects who had been using oral contraceptives had lower erythrocyte riboflavin status. This was assessed by the glutathione reductase test and was lower in the women who had been using oral contraceptives for the longest periods of time. A direct linear correlation between riboflavin status and glutathione peroxidase levels was observed. The most commonly used types of oral contraceptive in this study were of ethinyloestradiol-levonorgestrel formation, but it appeared that all the steroids investigated had produced statistically significant elevations in glutathione peroxidase after more than seven months usage. The possible significance of the elevation of this enzyme is discussed.