The production of fatty livers in rats on threonine-and lysine-deficient diets.

While studying the nicotinic acid-tryptophan relationship in rats on low casein rations containing choline (2), yellowish livers were observed on autopsy. These livers upon analysis were found to contain 16 per cent lipide. When an amino acid mixture containing threonine, valine, and histidine was added to the ration, normal liver lipides were found. A systematic study of the effects of these amino acids indicated that the fatty livers were the result of a suboptimal intake of threonine and could be prevented by the inclusion of adequate amounts of the amino acid in the diet. Similar results have been obtained with amino acid diets simulating the low casein rations. The possibility that deficiencies of other amino acids might lead to a similar abnormal accumulation of liver lipides was investigated. Under certain dietary conditions suboptimal intakes of lysine, tryptophan, and leucine resulted in fatty livers. The results of the threonine and lysine experiments are presented here.