Renal and extrarenal use of glutamine in normal and acidotic dogs

The total body clearance of glutamine in five normal and four acidotic dogs was estimated from the kinetics of disappearance from the blood of 14C-[U]-L-glutamine administered in a central vein as a single bolus. The disappearance curve was analyzed as reflecting a biexponential phenomenon with both a mixing and a metabolism component occurring, respectively, in the extracellular (mixing) and intracellular compartment (metabolism). The apparent total body metabolism of glutamine (total body clearance x arterial concentration) was compared with the renal use of this aminoacid as directly determined by renal A-V differences and blood flow. It was demonstrated that the renal use of glutamine represents between 13% and 25% of the total body use, and was increased by acidosis, which did not change significantly the overall rate of synthesis or use.