Abstract
The reason why the clinical signs of riboflavin deficiency appear chiefly on mucous membrane has not yet been elucidated. In a previous paper, we demonstrated that the activities of flavin enzymes other than DPNH-diaphorase were decreased remarkably by riboflavin restriction on the intestinal mucosa in which mitotic division is active. The present investigation was concerned with the effect of riboflavin deficiency on the cell renewal rate. We compared the incorporation of radioactive phosphorus into the deoxyribonucleic acid of the cell nucleus of mouse intestinal mucosa in riboflavin or iron deficiency. The following results were obtained : The incorporation of ^<32>P into the DNA was even greater in chronic riboflavin deficiency, while the incorporation was more slight in chronic iron deficiency. Such results are supposed to show that the mucous epithelial cells are renewing as usual or even more greatly in riboflavin deficiency though the regenerating cells are immature.
