Serum lipids in oophorectomized women during estrogen and testosterone replacement therapy

To evaluate the effects of giving testosterone undecanoate (TU) in addition to estrogen replacement on serum lipids in oophorectomized women.

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.

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.

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.