Studies on fatty acid esters of flavins: XIV. Excretion of riboflavin into urine of rat after injection of 14C-labeled riboflavin tetrabutyrate
Yagi, Kunio; Okuda, Jun; Yamada, M.
Vitamins kyoto 35(1): 45-49
Riboflavin- 2C14 and its tetrabutyrate were injected to rats and the excretion of riboflavin into urine was studied. In the case of riboflavin-2C14 injection (400 [mu]g, total counts 2.19 x 105 cpm [counts per min.], 301.6 [mu]g (total counts 4.89 x 104 cpm) of riboflavin was excreted into urine during 24 hr. after the injection. In the case of riboflavin tetrabutyrate-2C14 injection (400 [mu]g, total counts 2.19 x 105 cpm), only 182.0 [mu]g (total counts 1.74 x 104 cpm) of riboflavin was excreted into urine during 72 hr. after the injection. These results confirmed the previously reported fact that riboflavin-C14 moiety of riboflavin tetrabutyrate-C14 is effectively incorporated into FAD and FMN of organs and stays in animal body for a long time.