Antilipotropic effect of methionine in rats fed threonine-deficient diets containing choline.

In previous studies (l-5), dealing with the effects of different amino acids on fat deposition in the livers of rats fed low protein diets containing choline, 9 per cent casein diets have been supplemented with either methionine or cystine. Fat accumulates in the livers of animals fed this basal diet but in a preliminary experiment, in which the sulfur amino acids had been omitted, no excessive accumulation of fat was observed. Since the amounts and proportions of sulfur amino acids in the diet affect very markedly the development of fatty livers in animals fed diets deficient in choline, it was of interest to examine further the way in which the sulfur amino acids affected fat deposition in the livers of young rats fed diets containing choline. Since supplementation with threonine prevents the accumulation of fat in the livers of animals fed the 9 per cent casein basal diet (1, 3), and since the inclusion of tryptophan reduces the effectiveness of threonine under certain conditions (5), an attempt has also been made to determine whether any interrelationship exists between the effects of these two amino acids and that of methionine.