Sex steroids imprinting and prostatic growth.

Sex steroids exposure to rats castrated at birth during the neonatal or prepubertal period permanently modified certain morphologic features of the accessory sex organs in adulthood. Similar treatment of intact rats failed to induce these changes. Hypophysectomy in adulthood did not abolish the neonatally androgen-induced imprinting of the growth response of the rat accessory sex organs in adulthood, which suggests that the effects of neonatal androgen administration are directly on the hormone-responsive target cells and are not mediated via the hypothalamic-pituitary axis.