Effect of acute metabolic acidosis on the renin-aldosterone system. Mechanism of increases in plasma aldosterone in dogs infused with lactic acid.

Recent observations suggest that PA increases during acute metabolic acidosis. The pathophysiological mechanism(s) involved remains undefined. In the present study, anesthetized mongrel dogs were infused with lactic acid (10 mEq/kg body weight) for 3 hr. During acidosis there was no change in plasma potassium concentration, a tendency for an incrase in PRA, and significant increases in PC (as a marker for ACTH secretion) and PA. Other dogs were infused with lactic acid after prior treatment with dexamethasone and propranolol or with dexamethasone alone. Under these conditions, the development of acidosis was not associated with changes in PC, plasma potassium, PRA, or PA, suggesting that the stimulatory effect of acidosis on PA is not a direct one but is mediated by concomitant increases in ACTH and/or PRA.