Abstract
The data are given for the concentration of the three riboflavin fractions in several major tissues(liver, kidney, heart, lung, brain, spleen, gastric muecle, intestines and testicles), of both normal and riboflavin-defficient rats. Riboflavin content of the liver, kidney and heart of normal rat was about 20-30μg/g., and much lower in other tissues. In general, the majority of total riboflavin content, including free riboflavin, FAD and FMN, was FAD amounting to 65-85 per cent, while the remainder was almost FMN, and free riboflavin was insignificant in all the tissues. In riboflavin-defficient rat, all the three riboflavin fractions decreased, and the most significant decrease was found in FAD of the liver, kidney and heart. No significant change was recognized in the ratio of free riboflavin : FMN : FAD in the riboflavin-defficient tissues examined as compared with that of normal tissues.
