THE EFFECTS OF ALTERATIONS OF PLASMA SODIUM AND POTASSIUM CONCENTRATION ON ALDOSTERONE SECRETION*

Abstract

Intravenous infusion of KC1 or K2SO4 augmented the rates of aldosterone and corticosterone secretion in hypophysectomized dogs. The response was observed with an increment in plasma K as small as 1.3 meq per liter. Porter-Silber chromogen output was also increased in the two dogs with the largest increments in corticosterone production. Subsequent nephrectomy failed to block the response in aldosterone and corticosterone secretion to hyperkalemia in some animals, and in others the secretion of both steroids fell following nephrectomy. Infusion of KC1 or K2SO4 into the arterial supply of isolated adrenals increased aldosterone secretion. This finding provided evidence for a direct effect of the K ion on the adrenal cortex. In normal, intact dogs, a high K diet resulted in an increase in plasma K equivalent to the hyperkalemia that augmented aldosterone secretion during intravenous infusion of K. Under these circumstances urinary aldosterone excretion was elevated in association with the peak of the postprandial response in plasma K to the dietary K load. Infusion of 5% glucose in water into the arterial supply of isolated adrenals produced a reduction in plasma Na and an increase in aldosterone secretion.