Evidence that a humoral agent stimulates the adrenal cortex to secrete aldosterone in experimental secondary hyperaldosteronism.

The mechanisms which effect alterations in the secretion of aldosterone by the adrenal cortex may be nervous, humoral or both. The present study was undertaken to examine the possibility that a humoral agent stimulates the adrenal cortex to secrete aldosterone in dogs with experimental secondary hyperaldosteronism produced by constriction of the thoracic inferior vena cava. These animals secrete large amounts of aldosterone (1) and show almost complete retention of Na (2). To test the hypothesis of a humoral mechanism, the effect on aldosterone secretion was studied in normal recipient animals or in the isolated adrenals of normal dogs during cross-circulation of blood from dogs with constriction of the thoracic inferior vena cava. Corticosterone secretion was also measured to evaluate the possible role of adrenocorticotropic hormone (ACTH) in the aldosterone regulatory system.