Low testosterone levels are associated with endothelial dysfunction in oophorectomized early postmenopausal women

Abstract

The actual consequences of low testosterone levels in women remain uncertain. To assess endogenous testosterone influence on body composition, vascular and metabolic function in recent postmenopausal women. We studied 81 postmenopausal women under transdermal estradiol (E2) replacement therapy, 36 with bilateral oophorectomy (group O), and 45 controls (group C) through venous occlusion plethysmography, bioimpedance, DEXA, biochemical, hormonal, and inflammatory profile. Total testosterone level (TT) in group O was 11.0 (4.0-17.75) vs 23.0 (10.0-42.5) ng/dl in group C (P=0.001). Forearm blood flow, in ml/min/100 ml tissue, was lower in group O compared to group C at baseline (1.57 (1.05-2.47) vs 2.19 (1.59-2.66) P=0.036), following reactive hyperemia response (endothelium-dependent flow mediated dilatation, 3.44 (2.38-4.35) vs 4.3 (3.09-5.52), P=0.031) and following nitroglycerin (endothelium-independent dilation, 1.39 (0.99-1.7) vs 1.76 (1.15-2.0), P=0.025), with a positive correlation between TT and all parameters except for the reactive hyperemia response (r=0.233-0.312, P=0.036-0.004). The sVCAM1 levels were negatively correlated with TT (r=-0.320, P=0.005). E2 and other hormone levels, biochemical parameters and body composition did not differ between groups. Multiple linear regressions showed that the levels of TT, compared with other confounding variables, may explain the variation observed on endothelial parameters, with low explanatory power. The absence of ovarian testosterone production in recent postmenopausal oophorectomized women was associated with deleterious effects on endothelial function.