Androgens induce prolactin production by human endometrial stromal cells in vitro

Although there is a significant quantity of androgens in the endometrium, the function of these hormones has not been clarified, except for being estrogen precursors. Human endometrial stromal cells (ESC) were cultured in the presence of testosterone (T) and 5 alpha-dihydrotestosterone. Following culture, prolactin (PRL), a biochemical marker of stromal cell differentiation (decidualization) which is produced by ESC, was examined. T induced PRL production in a time- and dose-dependent manner, as reported previously for progesterone (P) stimulation. In addition, 5 alpha-dihydrotestosterone, which cannot be converted to estrogens, similarly induced PRL production. T in combination with P enhanced PRL production in cultured ESC significantly more than either P or T stimulation alone. A specific androgen receptor blocker, flutamide, when added to cultures containing T, inhibited PRL production in a dose-dependent manner, but did not affect the production of PRL induced by P. These results indicate that in vitro PRL production by human ESC is induced not only by P, but also by androgens through specific receptors and further suggest that androgens play an important role in human endometrial differentiation.