Endocrine Abstracts

Since estrogens are known to have some antiatherosclerotic properties and influence on endothelial function, including nitric oxide (NO) synthesis, the purpose of this study was to determine NO_x levels after menopause and to find whether the administration of estrogen therapy restores plasma NO_x levels back to normal. The study group consisted of 26 women with surgically induced menopause, mean age 50.9±2.9 years, and the controls were 40 healthy pre-menopausal women, mean age 48.3±2.3 years. Post-menopausal women were treated for four months with transdermal estradiol. Blood samples were collected for estimation of E₂, FSH, NO_x and lipid profile before and after therapy. Serum NO_x concentration in the study group was significantly lower than in controls (P<0.01) and it increased after treatment (P<0.01) reaching the values observed in the controls. The statistical analysis showed significant correlation between NO_x concentration and E₂ concentration in menopausal group before (r=0.25, P<0.05) and after (r=0.46, P<0.001) treatment. TC, LDL-C, TG, and azpo-B levels were higher in postmenopausal group comparing to controls, and after estrogen therapy they decreased to the values observed in the control group. HDL-C and its subfractions were lower in postmenopausal women than in controls and they improved after hormonal therapy. The same tendency was observed concerning apo-A1. There were no correlations between NO_x and lipids or apolipoproteins. We conclude that low E₂ levels in postmenopausal women were associated with lower NO_x levels. Estrogen therapy improves NO synthesis and relaxation of the vessels.