AJP - Regulatory, Integrative and Comparative Physiology, Vol 249, Issue 4 455-R461, Copyright © 1985 by American Physiological Society
Effect of aldosterone on potassium excretion during potassium chloride infusion in sheep
L. Rabinowitz, R. L. Sarason and H. Yamauchi
Experiments were performed on normal mature ewes to quantitate the effect
of acute variations in aldosterone activity on renal K excretion. Six-hour
clearance studies were performed on three sheep. Treatments were control
(no infusion), infusion of KCl (140 meq in 2 h) alone or with superimposed
infusions of aldosterone (20 micrograms/h), or infusion of aldosterone
antagonist potassium canrenoate (100 mg/h). During KCl infusion there were
simultaneous increases in plasma K, K excretion, and Na excretion.
Aldosterone treatment diminished the increase in plasma K and in Na
excretion but increased the rate of K excretion. Canrenoate had opposite
effects. The rate of change of K excretion relative to the change in plasma
K was 417 for aldosterone and 102 microeq/min per meq/l for canrenoate
treatments, P less than 0.05. Before KCl infusion aldosterone decreased the
rate of Na excretion and the salivary Na-to-K ratio but did not alter
plasma K or K excretion. Aldosterone has a potent kaliuretic action in
sheep when plasma K is elevated.
