Masculinization of toad pretrigeminal nucleus by androgens.

The magnocellular portion of the pretrigeminal nucleus (a structure involved in vocalization) of male toads contains large cells than does the female nucleus. Testosterone propionate injections caused essentially complete, and dihydrotestosterone injections incomplete, mascullinization of the female nucleus. Estradiol benzoate injections had little or no effect. The androgen effects are therefore largely direct rather than involving extensive aromatization of androgen to estrogen.