The Effect of Peptone and Amino Acid Ingestion upon the Concentrations of Tissue Amino Acids

Abstract

At various intervals of time following the ingestion of relatively large quantities of peptone, determinations were made in rats of the concentrations of 9 individual free amino acids in femoral muscle, liver, kidney, and spleen. In addition, measurements were made of variations in the individual non-protein bound amino acids of these tissues. The results indicate that the concentrations of individual amino acids within a single tissue undergo independent changes in response to the ingestion of peptone. Supplementation of normal diets with large quantities of dl-methionine resulted in increased concentrations of methionine in plasma and muscle, but lower levels in kidney and liver tissue. Arginine and phenylalanine levels also decreased in kidney. On a diet containing high concentrations of dl-phenylalanine, no significant changes occurred in muscle and liver tissue and in plasma; contrary to what occurred on the high methionine diet, the levels of arginine and phenylalanine rose in the kidneys of fasted rats; kidney methionine concentrations did not change appreciably.