Abstract
The heat production rates of riboflavin deficient rats were almost equal to those of normal ones at 20-23℃ at the 1st period of feeding, 0-3 weeks after the beginning of the test, but after the 2nd period, 6-7 weeks feeding, the rates of deficient rats were 15-20% less than those of normal. The values of K' derived from Benedict's formula were almost same in the two groups at the 1st period, but after the 2nd period, K' values of deficient groups gradually decreased as compared with those of normal. When the animals were put suddenly into the room of 5℃, after 9-10 weeks feeding, it was required 2.5 hours for normal animals to attain the constant maximal heat production rate which was 1.4 fold of that at 20-23℃, whereas in deficient rats only 35-40% of the maximal rate was produced. It was discussed that these results would be attributed to the decline of metabolic rates of substrates in the liver of riboflavin deficient rats, resulted from the small turnover rate of DPNH due to the decrease in activities of some special flavin enzymes, i.e., xanthine oxidase, glycolic acid oxidase and glycine oxidase.
