Acute effects of hypophysectomy and diencephalic lesions on aldosterone secretion

Abstract

Acute effects of hypophysectomy and of diencephalic lesions on aldosterone and corticosterone secretion were studied in 10 dogs with chronic experimental ascites. During preliminary observations, diencephalic lesions were made by the oral approach but the pituitary gland was damaged; in two dogs aldosterone and corticosterone secretion fell markedly. In the third animal, ACTH was given following the lesion; aldosterone failed to fall while corticosterone declined slightly. In the definitive study (7 dogs), hypophysectomy was performed before the diencephalic lesion was made. Following hypophysectomy, a 76–97% decrease in aldosterone secretion occurred within 2 hours. The effects of diencephalic lesions were variable; aldosterone output was unchanged, increased, decreased and increased during the 1st hour but declined thereafter. Corticosterone secretion fell 81–99% after hypophysectomy. These acute observations show a striking dependence of aldosterone and corticosterone secretion upon intact pituitary function. The evidence on the relation of the diencephalon to aldosterone secretion was inconclusive but an intact middle and posterior hypothalamus was not essential for normal or elevated rates of aldosterone secretion.