NEW YORK (Reuters Health) Mar 04 – Methyltestosterone, a widely used component of hormone replacement therapy (HRT), is a competitive aromatase inhibitor, according to a new report. Hence, by inhibiting estrogen production, the drug could have a beneficial effect on hormone-sensitive cancers.
Dr. Frederick Naftolin, from Yale University in New Haven, Connecticut, and colleagues evaluated the effects of methyltestosterone in a choriocarcinoma cell line and in a leukemia cell line. In the choriocarcinoma line, the cells constitutively expressed high levels of aromatase, while in the leukemia line the cells only expressed aromatase after undergoing differentiation.
In both cell lines, methyltestosterone inhibited aromatase activity in a dose-dependent fashion, the investigators note in the March 1st issue of The Journal of Steroid Biochemistry and Molecular Biology.
"Methyltestosterone is an orally active androgen preparation," Dr. Naftolin told Reuters Health. "It is typically used as an adjuvant to regular HRT, and it is approved by the US Food and Drug Administration for the treatment of decreased libido," he said. "But, the mechanism by which it works has been unclear," he added. …