Comparison of estrogen and androgen levels after oral estrogen replacement therapy.

OBJECTIVE

To assess the extent of accumulation of circulating estrone (E1), total and free estradiol (E2) and estrone sulfate (E1S) levels in postmenopausal women receiving prolonged oral E2 therapy and to determine the effect of increased estrogenicity on free testosterone levels.

STUDY DESIGN

Descriptive study involving 14 healthy postmenopausal women during a three-year period. Group 1 (n = 7) took a placebo. Group 2 (n = 7) took 1 mg micronized E2 daily. Blood samples were taken at one, two and three years. E2, E1 and total testosterone were quantified by radioimmunoassay (RIA) following extraction and celite chromatography. Free testosterone and E2 were calculated. Sex hormone-binding globulin (SHBG) and E1S were quantified by RIA.

RESULTS

In the control group, none of the hormone levels changed significantly. Free testosterone decreased 49% in women taking E2 replacement as compared to a 7% decline in women taking placebo. In women taking E2 replacement, E1, E2, E1S, free E2 and SHBG levels increased 10, 6, 51, 2 and 2 times, respectively, between baseline and year 3.

CONCLUSION

E1, E2 and E1S levels significantly increased with E2 replacement. Free testosterone levels decreased with E2 replacement. Testosterone replacement may be warranted when giving postmenopausal women estrogen replacement therapy.