Plasma amino acids in children and adolescents on hemodialysis

Fasting plasma amino acid concentrations were measured in 16 children on regular hemodialysis for renal failure. Reductions compared to normal were found in valine, leucine, isoleucine, lysine, histidine, tyrosine, and serine; and increases were found in glycine, citruline, proline, and 1- and 3-methylhistidine. Acute reductions in amino acid concentrations occurred in response to i.v. glucose, similar to those reported in normal adults, but plasma alanine, which was raised only in those with poor glucose tolerance, fell to normal and did not vary in those with normal glucose tolerance. No correlations were found with growth, but the plasma glycine concentration was highest in those patients with poorest energy intakes. Plasma alanine concentrations correlated with raised triglyceride concentrations. It is suggested that many of the abnormalities are due to the excessive utilization of protein for energy because of impaired availability of conventional energy sources in uremia.