Relationship between blood pH and potassium and phosphorus during acute metabolic acidosis

Metabolic acidosis is known to be associated with increased blood potassium and phosphorus concentrations but the influence of mineral versus nonmineral acids on these variables remains undefined. Therefore, we infused anesthetized mongrel dogs with 0.45% saline (controls), the mineral acids HCl and NH4Cl, and the nonmineral acids lactic, beta-hydroxybutyric and methyl malonic for 1-3 h. Administration of both mineral acids was associated with significant increases in plasma potassium. In contrast, infusion of the three monmineral acids did not result in increases in plasma potassium; in fact, the levels decreased initially in the majority of the dogs. Phosphorus concentrations were increased by lactic and beta-hydroxybutric acids, were unchanged by NH4Cl and HCl, and were decreased by methyl malonic acid. Although the mechanisms responsible for these changes remain to be elucidated, the findings indicate that short-duration infusion of mineral and nonmineral acids has substantially different effects on plasma concentrations of these predominantly intracellular ions.