PHYSIOLOGICAL REQUIREMENT OF ALDOSTERONE ACTION ON THE NA+ K+ PUMP INADH-STIMULATED NA+ ABSORPTION IN RENAL EPITHELIUM/

Short-circuit current measurement in renal epithelium (A6) indicated t hat the amount of antidiuretic hormone-stimulated Na+ entry in aldoste rone-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 antidiur etic hormone-activated Na+-permeant channels in the apical membrane. T he present study concludes that the stimulatory action of aldosterone on the Na+/K+ pump is a physiological requirement in antidiuretic horm one-stimulated Na+ absorption.