抄録
Fatty liver is caused when rats are given orotic acid of the pyrimidine base in large quantities. The lack of B-group vitamins suppresses the biosynthesis of fatty acids. We investigated how orotic acid-induced fatty liver affects the concentrations of liver, blood, and urine B-group vitamins in rats. The vitamin B6 and B12 concentrations of liver, blood, and urine were not affected by orotic acid-induced fatty liver. Vitamin B2 was measured only in the urine, but was unchanged. The liver, blood, and urine concentrations of niacin and its metabolites fell dramatically. Niacin and its metabolites in the liver, blood, and urine were affected as expected. Although the concentrations of vitamin B1, pantothenic acid, folate, and biotin in liver and blood were decreased by orotic acid-induced fatty liver, these urinary excretion amounts showed a specific pattern toward increase. Generally, as for the typical urinary excretion of B-group vitamins, these are excreted when the body is saturated. However, the ability to sustain vitamin B1, pantothenic acid, folate, and biotin decreased in fatty liver, which is hypothesized as a specific phenomenon. This metabolic response might occur to prevent an abnormally increased biosynthesis of fatty acids by orotic acid.
