Effect of aminoglutethimide on extraglandular metabolism of exogenous testosterone

Aminoglutethimide (AG), an inhibitor of steroid biosynthesis, seems to have an extraglandular site of action on steroid catabolism. To study this effect, five males with peripheral hypogonadism were first given testosterone propionate and then the same dose was repeated combined with AG and urinary testosterone, and its metabolites were measured. AG was shown to have a very evident effect on the peripheral degradation of exogenous testosterone. This may be responsible for a few signs of virilization and fetal masculinization in women taking AG.