THE EFFECT OF ACIDOSIS ON THE LABELING OF URINARY AMMONIA DURING INFUSION OF [AMIDE-N-15]GLUTAMINE IN HUMAN-SUBJECTS

In three experiments [amide-N-15]glutamine was infused intravenously i n male volunteers. After 4-8 h of infusion acidosis was achieved by an oral dose of CaCI2 (1 mmol/kg). In one subject acidosis was maintaine d for 5 d. The acid load produced an approximately 3-fold increase in urinary NH3 excretion, with a small (approximately 20 %) and transient increase in the isotope abundance of urinary NH3. Estimates of glutam ine production rate (flux) were obtained in two experiments. There was no evidence that it was increased in acidosis. The extra NH3 producti on by the kidney represented only a very small part, about 3%, of the total glutamine production rate.