The relationship of plasma glutamine to renal metabolism in acute acidosis

Rats were made acidotic with NH₄Cl and HCl given intragastrically. Both agents induced similar degrees of acidosis 30 min, 1 hr, and 2 hr after the acid load. The blood ammonia increased in response to acidosis but the rise was more rapid in the animals which were given NH₄Cl. Plasma glutamine also increased significantly as a response to acidosis. Glutamine was infused intravenously for 24 hr in concentrations of 250 and 100 mm but neither concentrations caused the increase in renal ammoniagenic capacity or phosphoenol pyruvate carboxykinase activity such as occurred when rats were made acidotic by infusion of NH₄Cl (125 mm) for 24 hr. Preincubation of renal cortical slices with glutamine also failed to enhance ammoniagenic capacity. The elevation of plasma glutamine is therefore unlikely to be signal for the renal metabolic adaptation to acidosis.