Effect of Methionine and Riboflavin on Free Amino Acids, Riboflavin and Lipids in Selected Rat Tissues

The effect of riboflavin and methionine supplementation of a riboflavin-deficient ration which contained 18% of casein, on the concentration of amino acids in plasma and riboflavin-containing coenzymes, cholesterol and total lipids in liver of rats was studied. The addition of 0.2% of l-methionine to a riboflavin-deficient basal ration which contained 18% of casein decreased the concentration of plasma valine in young rats fed 10 µg of riboflavin. A marked increase in plasma methionine was observed in animals fed 2.0% of methionine. A comparison of data for animals fed 2.0% of methionine and the basal ration showed an increase in plasma lysine for animals fed 10 µg of riboflavin.