Initiating Activity of Diethylnitrosamine in a Rapid Production Model for Pancreatic Carcinomas in Syrian Hamsters

The potential initiating activity of diethylnitrosamine (DEN) was studied in a rapid production model for pancreatic carcinogenesis in hamsters developed in our laboratory incorporating the principle of selection based on resistance to cytotoxicity, originally demonstrated for liver carcinogenesis in rats. Female Syrian golden hamsters were given DEN at a dose of 100 mg/kg body weight or N‐nitrosobis‐(2‐oxopropyI)amine (BOP) at a dose of 70 mg/kg body weight as initiators followed by 3 cycles of augmentation pressure (choline‐deficient diet combined with DL‐ethionine, L‐methionine upon return to basal diet and then administration of 20 mg/kg body weight BOP), and killed 10 weeks after the beginning of the experiment. DEN followed by the augmentation pressure induced a 65% incidence of total pancreatic lesions including 15% carcinomas, while BOP followed by the augmentation pressure induced 100% incidence of total pancreatic lesions and 84.2% for carcinomas. These yields were significantly greater than those observed for augmentation pressure alone. The results thus indicate that DEN possesses weak initiating activity for pancreatic carcinogenesis under the present experimental conditions.