The Relationship between Dietary Riboflavin Concentration and the Tissue Concentration of Riboflavin-Containing Coenzymes and Enzymes
Lucile E. Decker1 and
Richard U. Byerrum
The Departments of Foods and Nutrition and Chemistry, Michigan State College, East Lansing
1. The riboflavin intake necessary to maintain maximum tissuelevels of riboflavin coenzymes varies with the organ and theparticular coenzyme. In general, an intake of 30 µg perday was required to give maximum FAD and FMN concentrationsin all tissues.
2. The FAD and the FMN + free riboflavin concentrationsin brainwere almost independent of the amount of riboflavinin the diet.However, in kidney and liver, coenzyme concentrationswere almostdoubled when the intake was increased from no addedriboflavinto 30 µg per day. In the heart muscle of riboflavin-deficientanimals the FAD concentration and the FMN concentration wereabout the same whereas in kidney and liver tissues FMN concentrationwas less than the FAD content.
3. The liver enzymatic activitydepended on the riboflavin intakein the same manner as thecoenzyme concentration. Both D-aminoacid oxidase and xanthineoxidase activity increase with increasedintake of riboflavin.Xanthine oxidase activity reached a maximumwith an intake ofabout 30 µg of riboflavin per rat perday. D-Amino acidoxidase activity, on the other hand, increasedup to an intakeof over 60 µg riboflavin per rat per day.
1 Part of the experimental data were taken from a thesis presentedby Lucile E. Decker in partial fulfillment of the requirementsfor the M.S. degree. Presented in part before the Instituteof Nutrition at Atlantic City, 1954.