EVIDENCE THAT A HUMORAL AGENT STIMULATES THE ADRENAL CORTEX TO SECRETE ALDOSTERONE IN EXPERIMENTAL SECONDARY HYPERALDOSTERONISM *

Abstract

To test the possibility of a humoral mechanism in the regulation of aldosterone secretion, cross-circulation experiments were performed between dogs with thoracic inferior vena cava constriction and secondary hyperaldosteronism and normal recipient animals. Cross-circulation was established through the femoral vessels, or the isolated adrenals of normal animals were perfused with blood from a hyperaldosteronemic donor. Control and recovery periods were obtained with the recipient''s blood or by cross-circulation of blood from a normal dog. Repeated determinations of aldosterone and corticosterone were made in adrenal vein plasma by the double isotope derivative method. Aldosterone secretion in the recipient or in the recipient''s isolated adrenals increased markedly in 9 of 10 experiments, and returned to the control level in the isolated adrenals of 5 dogs with recovery observations. Corticosterone secretion increased only slightly in 4 of 8 experiments. No consistent alterations in the concentrations of plasma Na and K were detected. During cross-circulation of blood from 8 normal dogs into the isolated adrenals of normal animals, aldosterone secretion was unchanged or decreased in all but 2 dogs; a slight increase in corticosterone secretion occurred in 1/2 of the animals. It is concluded that a humoral agent, possibly a hormone, stimulates the adrenals to secrete aldosterone in dogs with secondary hyperaldosteronism.