Some Interrelations of Dietary Protein,Molybdenum,Riboflavin and Calories on Liver and Intestinal Xanthine Oxidase. ∗

Abstract

Summary

The omission of riboflavin and/ or molybdenum from a 24% casein diet fed to weanling rats had no effect on liver xanthine oxidase within 2 weeks; a molybdenum deficiency in the presence or absence of riboflavin removed xanthine oxidase from the intestine almost completely, while a riboflavin deficiency in the presence of molybdenum gave levels of intestinal enzyme which were about one-half the saturation levels achieved by a diet containing both molybdenum and riboflavin. The oxidase: dehydrogenase activity of the enzyme present in the liver or intestine was not altered by a riboflavin or molybdenum deficiency. Restriction of the daily food intake to 23% of the ad libitum intake of a 24% casein diet or 25% of a 96% casein diet had no effect on liver or intestinal xanthine oxidase. The level of liver xanthine oxidase depended primarily on the protein content of the diet, and such values were the same whether the diet contained 0.04 or 1 mg of molybdenum per kg. Intestinal xanthine oxidase levels were determined primarily by the molybdenum content of the diet, but low protein diets allowed only intermediate levels of this enzyme to be achieved even in the presence of a large excess of molybdenum.