Factors affecting the nitrogen balance in chronic uremic patients receiving essential amino acids intravenously or by mouth.

Abstract

A dietary regimen employing a protein-poor diet (2.7–3 g N/day) supplemented by essential amino acids, given intravenously or orally, changed the nitrogen balance in severe uremic patients from a negative to a positive one. The addition of histidine to the essential amino acids further improved the nitrogen balance. No difference in the nitrogen balance was observed when intravenous (i.v.) and oral administration were compared. <sup>15</sup>N studies indicate that protein synthesis takes place preferably in the muscle cells when the amino acids are infused intravenously, whereas oral treatment resulted in preferential synthesis of plasma protein. Insufficient caloric intake, lack of non-essential nitrogen, potassium depletion, corticosteroid administration, infection or cardiac insufficiency have been found to cause a deterioration of the nitrogen balance and an increase of plasma urea or concentration. In preliminary studies, administration of human growth hormone (HGH) to uremic patients maintained on the protein-poor diet was found to further improve the nitrogen balance. In other preliminary experiments, administration of extra tryptophan with the diet amino acids to uremic patients was also found to improve the nitrogen balance.