Some Metabolic Effects of Methionine Toxicity in the Rat

Abstract

Rats consuming a 15% casein diet containing 4.0% of DL-methionine developed the following metabolic alterations in the liver: increased activities of arginase, tryptophan pyrrolase, glutamic-oxalacetic and pyruvic transaminase, decreased levels of DPN and slightly increased levels of total and neutral fat. However, the fat content approached a normal level at the end of the tenth week of the experimental period. Urinary excretion of a number of amino acids was also markedly increased. Supplementation of the high methionine diet with 4.0% of glycine decreased the activities of liver arginase and GOT, and increased the activity of GPT. The levels of some amino acids in the urine were also decreased by the supplemental glycine. The data indicate that ingestion of excess methionine leads to a severe disorder in nitrogen metabolism and that the supplemental glycine counteracts some of these metabolic derangements.