Effects of estrogen and estrogen-progesteron on serum nitric oxide metabolite concentrations in post-menopausal women

Abstract

Estrogens have some anti-atherosclerotic properties and they influence nitric oxide (NO) production. The aim of this study was to determine NOx levels in post-menopausal women and the effect of estrogen/estrogen-progesteron therapy (ET/EPT) on plasma NO levels. Eighty postmenopausal women (M1) comprising 26 with surgically induced menopause (ET1), mean age 50.9+/-2.9 yr, and 54 with physiological menopause (EPT1), mean age 50.5+/-3.0 yr, were studied. Forty healthy pre-menopausal women, mean age 48.3+/-2.3 yr were the controls (C). The post-menopausal women were treated for 4 months: group ET1 with ET and group EPT1 with EPT. Serum estradiol (E2), FSH, NOx and lipid profile before and after therapy were measured. NOx levels were lower in group M1 than in group C (8.75+/-1.57 vs 10.27+/-2.62, p<0.01) and increased after hormonal therapy (10.65+/-2.38). NOx concentration showed significant positive correlation with E2 (r=0.25, p<0.05). Total cholesterol (240.9+/-43.2), LDL-cholesterol (155.2+/-33.6), triglycerides (124.8+/-54.1), and apolipoprotein B (1.52+/-0.33) were higher in group M1 than in group C (223.1+/-44.3, 133.0+/-38.2, 108.3+/-52.9, and 1.12+/-0.36, respectively), and after ET/EPT they decreased to the values observed in group C. There were no correlations between NO and lipids or apolipoproteins. ET and EPT improve NOx synthesis and endothelial relaxation. Medroxyprogesterone acetate added to E2 does not significantly influence NOx levels.