Promoting effects of both dietary cholesterol and cholestyramine on pancreatic carcinogenesis initiated by N-nitrosobis(2-oxopropyl)amine in Syrian golden hamsters.

Abstract

The effects of dietary cholesterol and cholestyramine on pancreatic carcinogenesis initiated with N-nitrosobis(2-oxopropyl)amine (BOP) were investigated in 120 female Syrian golden hamsters. BOP (70 mg/kg body weight) was injected s.c. once at the beginning of the experiment. Starting 2 weeks later, the animals were then maintained on basal diet or diets containing either 0.5% cholesterol or 1% cholestyramine for a further 16 weeks. All surviving hamsters were killed at week 18, and the pancreas tissues examined histologically. The incidences of pancreatic carcinomas in hamsters fed cholesterol and the cholestyramine supplement were 40.0 and 30.0% respectively; in both cases significantly higher than the 6.9% incidence in the basal diet group. Cholesterol contents of the serum, pancreas and liver were significantly increased by cholesterol feeding and significantly decreased by the cholestyramine diet. The cholesterol diet also significantly increased pancreatic protein and DNA contents, and the concentration of total bile acids and the level of lithocholic acid in gallbladder bile. The cholestyramine diet significantly increased total pancreatic DNA and protein contents, and pancreatic weight. The results thus indicated that both dietary cholesterol and cholestyramine can enhance BOP-initiated pancreatic carcinogenesis in hamsters.