Previous studies have shown poor maintenance of adrenal weight and adrenocortical function when 1-4 pituitaries were heterotopically transplanted in hypophysectomized rats. In the present studies, hypophysectomized male rats bearing 10 heterotopic pituitary homotransplants maintained nearly normal adrenal weight. Adrenocortical secretion of corticosterone, aorta plasma corticosterone and adrenal corticosterone concentration were significantly higher than in hypophysectomized controls. These findings suggest that the amount of ACTH secreted in these animals is a function of the number of pituitaries transplanted. Suppression of corticosterone secretion by dexamethasone was similar in both transplanted and intact animals, indicating that contiguity of the pituitary with the hypothalamic median eminence is not essential for the suppression of ACTH secretion by corticosteroids.