In intact adult male rats an inhibitor of aromatase and an inhibitor of 5alpha-reductase did not change the characteristics of [H-3]imipramine binding sites in cerebral cortex, hypothalamus, and hippocampus. Testosterone, estradiol and dihydrotestosterone prevented the effect of castration on the number of [H-3]imipramine binding sites, but had no effect in non-castrated animals. These data suggest that testosterone and its major metabolites, estradiol and dihydrotestosterone, are equally effective with regard to imipramine binding sites
