Refection in rats fed on a sucrose-based, riboflavin-deficient diet.

1. Refection, resulting in an increased supply of riboflavin to riboflavin-deficient rats through coprophagy, was demonstrated on a sucrose-based diet when sensitive biochemical tests of riboflavin status were employed: these included measurements of NAD(P)H2:glutathione oxidoreductase (EC 1.6.4.2); succinate:(acceptor) oxidoreductase (EC 1.3.99.1) and NADH:(acceptor) oxidoreductase (EC 1.6.99.3). 2. The use of tail-cups to eliminate coprophagy, and hence refection, resulted in a more rapid and reproducible progress into severe deficiency. 3. The occurrence of refection on a sucrose-based diet may account for hitherto unexplained differences between previous publications on the biochemical effects of riboflavin deficiency.