A[fort COMPARISON OF THE CARCINOGENIC ACTIVITIES ON THE LIVER OF DIETHYLNITROSAMINE AND p-DIMETHYLAMINOAZOBENZENE
Earlier experiments carried out with the liver carcinogen p-dimefhylaminoazobenzene ( D A B ) have been repeated with another liver carcinogen, diethylnitrosamine ( D E N ) .
Nine different experiments were perfbrmed, using 84 male Wistar rats. The results were the reverse of those obtained with DAB. With the latter, a protein-poor diet or a simultaneous administration of reserpine accelerates the process of cancerization, while addition to the carcinogen of certain phenolic ketones or of o,p'-dichlorodiphenyldichloroethane ( 0 , ~' -D D D ) inhibits it. With DEN, neither variations in the diet nor reserpine have any marked effect on the cancerization process, while the phenolic ketones and o,p'-D D D accelerate it.
DAB is far more toxic to the hepatocytes, whereas DEN is more toxic to the cells of the connective-vascular system of the liver.
As is the case with DAB, the carcinomas produced by DEN have their origin in biliary stem-cells, the different histological types of the tumours merely representing varying degrees of cellular differentiation.