We examined the effect of hypophysectomy in rats on peripheral-type benzodiazepine receptors in the adrenal gland and testis. Following removal of the pituitary, binding sites for [3H]Ro5-4864, a ligand selective for peripheral-type benzodiazepine receptors, are depleted in these tissues in parallel with their atrophy. This reduction in receptor levels appears to be a primary effect of the hypophysectomy, since castration has no effect on benzodiazepine receptors in the adrenal gland, nor does adrenalectomy influence testicular levels of these receptors. Our results indicate that peripheral-type benzodiazepine receptors in these steroidogenic organs are localized to cells which are dependent on trophic maintenance by the pituitary.