Physiological requirement of aldosterone action on the Na+/K+ pump in ADH-stimulated Na+ absorption in renal epithelium.

Short-circuit current measurement in renal epithelium (A6) indicated that the amount of antidiuretic hormone-stimulated Na+ entry in aldosterone-treated cells exceeded the ability of the Na+/K(+)-pump to extrude Na+ in aldosterone-untreated cells. This suggests that, if aldosterone has no stimulatory action on Na+/K(+)-pump activity, the activity of Na+/K(+)-pump is not large enough to extrude Na(+) entering through antidiuretic hormone-activated Na(+)-permeant channels in the apical membrane. The present study concludes that the stimulatory action of aldosterone on the Na+/K+ pump is a physiological requirement in antidiuretic hormone-stimulated Na+ absorption.