Abstract
p-Dimethylaminoazobenzene (D. A. B.) was fed to rats after preliminary in-jections of carbon tetrachloride (CCl4), and the following results were obtained.
1) The preliminary injections of CCl4 accelerated and intensified D. A. B. -induced early histological changes in the liver. The carcinogenic action of D. A. B. on the liver was also reinforced by CCl4 pretreatment.
2) Liver cirrhosis due to CCl4 pretreatment had an accelerating action on the development of D. A. B. -induced liver carcinoma. This accelerating action of CCl4-induced liver cirrhosis on the hepatic carcinogenesis by D. A. B. was sustained, even when the cirrhogenie action of D. A. B. was suppressed by appropriate change in the composition of D. A. B. containing diet.
3) The relationship between lowered protein-bound azo-dye levels in the liver on account of preliminary CCl4 injection and the increased incidence of D. A. B. -induced hepatic carcinoma was discussed.
