Abstract
The body weight of riboflavin-deficient rat increesed 0.9 to 1.0g per day for 3 weeks after the beginning the test, and then decreased gradually. The weight of paired feeding normal rat, however, increased 1.4 to 1.9g and 0.4 to 0.5g, respectively. When each group received abruptly the protein-free diet, the weight of normal rat decreased markedly, while that of deficient rat decreased a little or not. The amounts of total nitrogen and urea in urine did not differ between the normal and riboflavin-deficient groups during the period when the animals received the diets with added protein. Furthermore, the decreasing patterns of those contents were not different between two groups when the animals were fed the protein-free diets. In addition, the weight of liver and total protein per body weight increased in the riboflavin deficient rat compared with the normal rat as reported previously. These facts indicate that the food protein was not utilized effectively in the riboflavin deficient animal, and the protein may be accumulated in the specific organ, probably in liver, without excretion in urine. Thus the effect of riboflavin deficiency can be explained on the basis of suppression of anabolism but not increment of catabolism.
