Elimination of amino acids in chronic renal failure.

Elimination of parenterally administered amino acids was investigated in patients with chronic renal failure (CRF) (10 on conservative treatment = CT, 13 on regular hemodialysis therapy = HD). In a bolus injection protocol 0.1 g amino acids as a 10% solution containing essential and nonessential amino acids were infused and pharmacokinetic parameters of 17 amino acids were calculated. The mean elimination half life was increased by 40% in CT and 87% in HD (p less than 0.001 CT and HD versus controls). Total clearance was reduced in CT (p less than 0.001 versus HD and controls). In CT clearance of phenylalanine, proline, alanine, histidine and arginine was reduced, of none of the amino acids elevated. In HD clearance of methionine, lysine, aspartic acid and serine was increased, of proline decreased. The total transfer rate was reduced in CT (p less than 0.025 versus controls) and transfer of threonine, aspartic acid, glutamic acid, alanine, histidine and arginine was reduced in these patients. Mainly due to elevated basal plasma concentration transfer of methionine was elevated in CT and HD. In dialysis patients transfer of isoleucine, tryptophan, glycine and serine was increased. Despite variations of absolute values of clearance between the two groups investigated relative clearance rates of amino acids were similar because of a uniform increase of clearance of about 37% in HD compared to CT (p less than 0.001). Results indicate that the elimination of parenterally administered amino acids is grossly altered in uremia and that in patients on CT and HD a uniform elimination pattern can be observed.