Sex-hormone binding globulin as an indicator of the hepatic impacts of continuous combined hormone replacement regimens.
OBJECTIVES: Nonoral administration of hormone replacement therapy avoids the first pass metabolism of steroids in the liver. We wanted to determine to what extent it has an effect on the serum concentrations of sex-hormone binding globulin and the free testosterone index. METHODS: Postmenopausal women received 50 microg per day transdermal estradiol associated with the use of a levonorgestrel-releasing intrauterine device (20 women) or a daily oral dose of 2 mg of estradiol and 1 mg of norethisterone acetate (20 women) for 1 year. Eight women, five in the nonoral and three in the oral therapy group discontinued the study. RESULTS: Although serum sex-hormone binding globulin concentrations decreased in women receiving transdermal estradiol in combination with a levonorgestrel-releasing intrauterine device, the free testosterone index did not change significantly. In the continuous oral regimen, no significant changes in serum sex-hormone binding globulin or free testosterone index were observed. The free testosterone index, however, was significantly higher in the nonoral therapy group after 6 and 12 months of treatment than in the oral therapy group. CONCLUSIONS: Continuous progestin combined with continuous estrogen in oral and nonoral replacement therapy does not lead to a substantial androgenic excess in postmenopausal women. The intrauterine administration of levonorgestrel appears to have some hepatic effect.