THE EFFECT OF POTASSIUM ON INTRACELLULAR BICARBONATE IN SLICES OF KIDNEY CORTEX 1

Abstract

Slices of rabbit kidney cortex depleted of K+ by leaching in isotonic NaCl were incubated in buffered HCO3- media with various substrates. With K+ - free media final tissue HCO3- concentrations were significantly lower than when K+ as added. Changes .vere dependent upon the intracellular accumulation of K+. In tissues with high K+, the higher tissue HCO3- was associated with a correspondingly lower tissue Cl-. Addition of Rb+ or Cs+ instead of K+ produced similar changes in tissue HCO3-. If free diffusion of CO2 is assumed, the results indicate an intracellular acidosis in K+ depleted tissues. Findings support the hypothesis that the pH of the renal tubules may directly influence renal excretion in regulation of acid-base balance in conditions of K+ depletion or excess.