ENDOGENOUS RENAL CLEARANCE RATES OF FREE AMINO ACIDS IN PRE-PUBERTAL CHILDREN (Employing an Accelerated Procedure for Elution Chromatography of Basic Amino Acids on Ion Exchange Resin)

Abstract

Six male and three female children in good health and between the ages of 3 and 10 years were studied. Fasting plasma concentrations and urine excretion rates of free amino acids were measured using automated ion exchange chromatography, utilizing a modified method for analysis of the basic amino acids. Endogenous clearance rates and net tubular absorption of plasma amino acids were also calculated. The plasma concentration of free amino acids is generally slightly lower than in the adult subjects and renal clearance rates are slightly higher. Less than 5% of the filtered amino acid load is excreted in the urine. Intra-individual variation tends to be smaller than inter-individual variation.