ROLE OF EPINEPHRINE-INDUCED HYPOKALEMIA IN THE REGULATION OF RENIN AND ALDOSTERONE IN HUMANS

Circulating epinephrine induces both stimulation of plasma renin activ ity (PRA) and a decrease in serum potassium concentration. This study was designed to determine the dose-response effects of systemic epinep hrine infusion on the relationship of PRA and plasma aldosterone conce ntration. Twenty-one men with normal blood pressure received either an intravenous infusion of epinephrine at 12.5, 25, and 50 ng/(kg x min) by stepwise increments for 1 hour each or isotonic saline solution, I nfusion of epinephrine led to a dose-dependent increase in plasma epin ephrine concentration, systolic blood pressure, and heart rate, wherea s diastolic blood pressure was decreased. PRA was elevated in a dose-d ependent manner, whereas the plasma aldosterone concentration was redu ced. During infusion of epinephrine, the serum potassium concentration and renal potassium excretion were significantly decreased, We conclu de that despite marked stimulation of PRA, the plasma aldosterone conc entration was further decreased because of a dose-dependent decrease i n serum potassium concentration induced by epinephrine. Thus hypokalem ia appears to be the predominant regulator of plasma aldosterone durin g incremental epinephrine infusion.