EFFECT OF POTASSIUM-CHLORIDE ON PLASMA-RENIN ACTIVITY AND PLASMA-ALDOSTERONE DURING SODIUM RESTRICTION IN NORMAL MAN

The present study was designed to evaluate the spectrum of responses of PRA [plasma renin activity] and plasma aldosterone (PAldo) to a range of oral K intakes (0-300 meq KCl/day) in 20 normal human subjects receiving an electrolyte-free diet. K exhibited a dose-dependent natriuretic effect. The results of the PRA studies indicate that normal dietary amounts (50 meq/day) of KCl do not prevent the increase in PRA with absolute Na deprivation and that PRA is maximally stimulated on 150 meq of KCl/day. The rise in PRA is directly correlated with serum K concentration. The results of the PAldo studies indicate that KCl deprivation attenuates PAldo increases due to Na deprivation and that PAldo is maximally stimulated on 150 meq of KCl per day. The rise in PAldo is directly correlated with serum K concentration and with PRA. The administration of 300 meq/day KCl caused significant hyperkalemia and blunted both PRA and PAldo increases. KCl has an important role in the regulation of PRA and PAldo, and that only following KCl deprivation is the PRA/PAldo response dissociated.