University of New Hampshire
Mentor: Joanne Curran-Celentano, Ph.D. - Associate Professor of Animal and Nutritional Sciences
The Effects of Endogenous and Exogenous Hormones on Serum and LDL Antioxidant Concentrations in Pre- and Postmenopausal Women
The risk of developing atherosclerosis increases with elevated LDL cholesterol. Oxidative modification of LDL is thought to be involved in the genesis and progression of the atheroma. Antioxidant nutrients, such as beta-carotene and vitamin E, have been shown to protect LDL from oxidation in vitro. It has also been suggested that estrogen, which lowers LDL cholesterol and increases HDL cholesterol, may influence the oxidation of LDL. Physiologic levels of estrogen may spare antioxidant nutrients in the LDL, ultimately inhibiting the progression of atherosclerosis.
The effects of endogenous and exogenous hormones, in pre- and postmenopausal women, on serum and LDL antioxidant concentrations was investigated. Twenty women aged 18-30 years old were recruited for phase I of the study. The women were placed into 2 groups: taking oral contraceptives (n=10) and not taking oral contraceptives (n=10). Blood was drawn at 5 time points throughout each of two consecutive menstrual cycles. Phase II involved a cohort of about 70 postmenopausal women, aged 50-65, participating in the UNH Women's Health Study. The subjects were grouped by hormone replacement use: estrogen, estrogen and progestin, or none.
Dietary evaluation and serum analysis allowed for quantification of total cholesterol, LDL cholesterol, and triglycerides, in serum, and beta-carotene and vitamin E, in diet and serum. The hormones estradiol and progesterone were measured using enzyme-linked immunosorbent assay (ELISA). Relationships of hormone status to serum and LDL antioxidant concentration and to the oxidizability of LDL were determined.