[GANN, 58, 267-281; June, 1967] UDC 616-006-021.6[616.36]:547.556.33:615.782.54-092.259 EFFECT OF BARBITAL ON CARCINOGENIC ACTION AND METABOLISM OF 4-DIMETHYLAMINOAZOBENZENE*1

To study the influence of activation of metabolic function of carcinogen to chemical carcinogenesis, effect of barbital, an inducer of enzymes related to drug metabolism, was studied on the development of liver cancer in the rat fed with 4-dimethylaminoazobenzene (DAB), and compared with that of 3-methylcholanthrene,*4 known to antagonize the carcinogenic effect of DAB. In an animal experiment of a long period, the incidence of cancer development was much lower in barbital group than that in 3-methylcholanthrene group. Comparative studies were also made on the quantitative measurement of DAB metabolites in urine and bile, and on the activities of some enzymes in the liver of rats fed with DAB plus barbital diet, DAB diet, or basic diet alone. Excretion of DAB metabolites, especially azo dye glucuronides, in the bile increased in the middle stage of the barbital feeding.