Degradation and Excretion of Riboflavin in the Rat

Publisher Website
Google Scholar
Abstract
Carbon-14-labeled riboflavin was injected intraperitoneally into young adult rats to study the degradation and excretion of the vitamin. The distribution of radioactivity 24 hours after administration was found to be high in the liver and kidney but very low in the blood. Almost all the radioactivity administered was recovered from urine, feces, and carcass at the end of the experiment. The radioactivity of these samples was due mainly to intact riboflavin, and except for lumichrome and lumiflavin no other degradative product of riboflavin was found. The ribitol side chain on position 9 of riboflavin was not degraded in the tissues. However, there was low production of lumichrome, lumiflavin, and CO2 from riboflavin by the intestinal microorganisms. The turnover rate of this vitamin in the body was affected by the level of its intake, a half-life of 16 days being observed for rats under normal physiological conditions. The maintenance requirement of riboflavin for the rat was shown to be dependent mainly upon excretion rather than decomposition of the vitamin.