Serum lipid peroxide levels and erythrocyte glutathione peroxidase and superoxide dismutase activity in premenopausal and postmenopausal women

Free radical reactions are involved in processes connected with aging. Estr adiol acts as antioxidant and free radical scavenger, but the mechanism of this action remains unknown. Estradiol has a hydroxyphenolic structure and may donate hydrogen atoms to lipid peroxyradicals to terminate chain reacti ons. There are a few reports concerning the influence of estradiol on natur al antioxidant enzyme activity, such as superoxide dismutase (SOD), glutath ione peroxidase (GSH-Px) and catalase (CAT). The aim of this study ws to es timate the relationship between the levels of estradiol and lipid peroxide (LPO), a marker of membrane lipid peroxidation, and the correlation between estradiol and erythrocyte SOD and GSH-Px activity. The study included 13 p remenopausal and 13 postmenopausal healthy women. Serum levels of estradiol , follicle-stimulating hormone (FSH) and LPO, and erythrocyte SOD and GSH-P x activity were estimated in all subjects. Premenopausal women revealed sig nificantly higher estradiol levels and lower LPO concentrations, as well as significantly higher GSH-Px activity than the postmenopausal group. SOD ac tivity did not differ between the two groups. There was a negative correlat ion between serum estradiol and LPO levels as well as a positive correlatio n between estradiol and GSH-Px activity. These results support the hypothes is that estradiol exerts its antioxidant action not only through its chemic al structure but probably also through its inf hence on natural cellular an tioxidant enzyme activity.