Effect of essential amino acid supplementation on muscle and plasma free amino acids in chronic uremia.

In chronic uremia patients on an 18-g protein diet for 2 to 3 weeks, the intracellular free amino acid pattern in muscle was grossly abnormal, with low concentrations of threonine, valine, carnosine, and high concentrations of aspartate, glutamine, glycine, alanine, and taurine. When the protein-poor diet was supplemented with essential amino acids (2 to 3 times that for minimum requirements) and histidine, these abnormalities were partly corrected. Other abnormalities, however, were observed, such as low intracellular concentrations of phenylalanine and tyrosine, and high concentrations of lysine, histidine, ornithine, and citrulline.