Abstract
Riboflavin-2-^<14>C or its tetrabutyrate was injected to rats and the excretion of riboflavin and its butyrate into bile and feces was studied. In the case of riboflavin-2-^<14>C injection (400μg, total count 2.19×10^5cpm), 41.25μg (total count 6.58×10^3cpm) were excreted into bile during 3 hours after the injection and 40.9μg (total count 2.07×10^3cpm) into feces during 72 hours after the injection. In the case of riboflavin tetrabutyrate-2-^<14>C injection (400μg in terms of riboflavin, total count 2.19×10^5cpm), only 6.75μg (total count 2.14×10^3cpm) of riboflavin and riboflavin tetrabutyrate was excreted into bile during 3 hours after the injection, 74.6μg (total count 4.68×10^3cpm) into feces during 72 hours after the injection.
