In three experiments [amide-15NJglutamine was infused intravenously in male volunteers. After 4-8 h of infusion acidosis was achieved by an oral dose of CaCl, (1 mmol/kg). In one subject acidosis was maintained for 5 d. The acid load produced an approximately 3-fold increase in urinary NH, excretion, with a small (approximately 20%) and transient increase in the isotope abundance of urinary NH,. Estimates of glutamine production rate (flux) were obtained in two experiments. There was no

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... that it was increased in acidosis. The extra NH, production by the kidney represented only a very small part, about 3%, of the total glutamine production rate. Acidosis : Glutamine metabolism: Urinary ammonia * Present address : Viscera and liver Normal V" 9 4 V" 6 4 + 3.0 Metabolism Acidotic V" 10.8 V"8.1 +2,7 Metabolism Normal V" 2.4 V" 4.7 -2.3 Synthesis Acidotic V" 0.9 V" 4.7 -3.8 Synthesis Muscle and peripheral tissues Kidney Normal Acidotic Production rate = V" + V" +V" Normal = 12.3 Acidotic = 13.1 V" 0.5 V" 1.2 -0 7 Urine V" 1.6 V" 0.3 +2.3 Urine V", V", V", flux from viscera, muscle and kidney respectively to central pool; V", V", V", flux from central pool to viscera, muscle and kidney respectively.