Objective: To evaluate the effects of giving testosterone undecanoate (TU) in addition to estrogen replacement on serum lipids in oophorectomized women.
Method: Women with surgically induced menopause (n = 50) were randomly assigned to oral treatment with 2 mg of estradiol valerate in combination with 40 mg of TU or placebo for 24 weeks. The study was double-blind with cross-over to the other regimen for further 24 weeks of treatment. Forty-four women completed the study. Their serum concentrations of total, high density lipoprotein (HDL)- and low density lipoprotein (LDL)-cholesterol, triglycerides, lipoprotein-(a) (Lp-(a)), total testosterone, estradiol and sex hormone-binding globulin (SHBG) were analyzed at baseline and after 24 weeks of each treatment.
Results: Serum levels of total testosterone increased markedly from a baseline mean of 0.8-4.9 nmol/l during testosterone addition. The levels of free testosterone significantly increased during the combined treatment and fell when given estrogen alone. Total and LDL-cholesterol levels were significantly reduced by both treatments as also were those of Lp-(a) although the difference was not significant. We found a 13% reduction in HDL-cholesterol levels when testosterone was added, but no change with estrogen alone. Triglyceride levels were increased by estrogen treatment, but not affected by the combination of estrogen plus testosterone.
Conclusions: These findings suggest that 40 mg of TU can be given in addition to estrogen replacement with only little side-effects on the pattern of circulating lipids. Although supraphysiological concentrations of testosterone were induced a significant reduction in total and LDL-cholesterol levels occurred.