cinogens, with observations on the effect of dietary riboflavin and pantothenic acid on the conjugation of 2-aminofluorene and on the formation of non volatile phenols in dogs. MATERIALS AND METHODS

in conjugation as the dietary riboflavin is raised from 0.025 to 0.25 to 2.5 mg/day/kg of body weight. These data were obtained by feeding the test level of vitamin for 7 days prior to administra tion of the carcinogen. Continued feeding of 2.5 mg. of riboflavin for 16 days increased the per centage of conjugation (expressed as conjugated aminofluorene) still further to an average of 51. Riggs and Hegsted (10) found that the conjuga tion of p-aminobenzoic acid was significantly lower in riboflavin-deficient rats than in the controls. On the other hand, Shils et at. (11) did not find ribo flavin to be a factor in the acetylation of sal The carcinogen 2-acetylaminofluorene, when fed to animals (0.03 per cent in the diet), produces a riboflavin deficiency and depletes protein stores, changes which can be prevented in part by increas ing the riboflavin and protein content of the diet (1, 4, 5, 14). The following studies are part of a program of research on the metabolism of car cinogens, with observations on the effect of dietary riboflavin and pantothenic acid on the conjugation of 2-aminofluorene and on the formation of non volatile phenols in dogs.