Acute stimulation of aromatization in Leydig cells by human chorionic gonadotropin in vitro.

Abstract

Aromatization of testosterone in Leydig cells purified from mature rat testes was assessed. Leydig cells incubated for 4 hr with increasing concentrations of [3H]testosterone. At saturating concentrations of testosterone, human chorionic gonadotropin (hCG) acutely stimulated aromatization. This stimulation was first observed at 1 hr, an 8-fold increase being found during a 4-hr incubation. The maximal amount of estradiol produced at saturating concentrations of testosterone and hCG was 1.8 ng per 10(6) cells. These results demonstrate that purified Leydig cells have a high capacity for aromatization and that hCG can acutely stimulate aromatization independently of stimulating testosterone synthesis in vitro.