Endocrine Abstracts (2006) 11 P666

The influence of estradiol on erythrocyte antioxidative enzyme system activity in pre- and postmenopausal women

G Bednarek-Tupikowska, U Tworowska & B Bidzinska Speichert

Dept. of Endocrinology, Diabetology and Isotope Treatment, Medical University of Wroclaw, Wroclaw, Poland.

Free radicals are continuously produced during normal metabolism. They play important role in the pathogenesis of atherosclerosis, carcinogenesis, degenerative processes of the brain and skin, and some diseases connected with aging. Among several natural antioxidants, estrogens are important free-radical scavengers due to the hydroxyphenolic structure of their molecules Some authors have suggested that estrogens may also influence the activity of the cellular antioxidative enzyme system, but these data remain controversial. The aim of our study was to investigate the effects of estradiol deficiency after menopause and the influence of estadiol therapy (ET) on cellular antioxidative enzyme system: erythrocyte dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) activity. Glutathione (GSH) and selenium (Se) concentrations were also estimated. Serum lipid peroxide (LPO) levels were measured as an indicator of free-radical production and cell membrane phospolipids peroxidation.

Materials and methods: The study group consisted of 26 women with surgically induced menopause and climacteric symptoms. Forty premenopausal healthy volunteers served as controls (C group). The postmenopausal women were treated for 4 months and received estradiol transdermally in a dose of 50 μg daily. The blood was collected for SOD, GSH-Px, CAT, GSH, Se and LPO estimation before and after therapy. The study protocol was approved by Ethical Committee of Medical University in Wroclaw.

Results: LPO was higher in postmenopausal women and decreased after ET. GSH-Px and GSH were lower in the postmenopausal groups, but increased significantly after estrogen therapy. Se concentrations did not differ significantly among the groups. CAT activities were similar in all groups and decreased after ET. SOD activities in postmenopausal women were similar to those in C group and did not change significantly after ET.

Conclusions: Our findings indicate that oxidative stress increased after menopause and the administration of natural estrogens to postmenopausal women diminishes oxidative stress and increases antioxidative cell potency.

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