Metabolism of lysine in isolated swine renal cortical tubules subjected to variations in extracellular pH, bicarbonate and CO 2

Abstract

The effects of an acute disturbance of acid-base variables -- pH, HCO 3 − and pCO 2 - - on the metabolism of lysine were investigated using isolated porcine renal cortical tubules. Three concentrations of HCO 3 − (12.7, 22.6 and 34.9 mM) and three levels of pH (7.20, 7.41 and 7.63) of incubation media were used to evaluate the effects of these variables on uptake and metabolism of L-[U- 14 C lysine. Freshly isolated tubules were incubated in modified Krebs-Henseleit buffer for 30 min in the presence of labelled substrate. Increasing pH resulted in higher rates of lysine degradation as measured by 14 CO 2 evolution during incubation, but did not alter the concentration of tubular free LYS. Increasing HCO 3 − concentration resulted in an 80% increase in the accumulation of tubular free LYS but no change in the evolution of 14 CO 2 . The experiments suggest that acute disturbance of acid-base balance may alter the renal metabolism of lysine.