Lack of influence of low blood cholesterol levels on pancreatic carcinogenesis after initiation with N-nitrosobis(2-oxopropyl)amine in Syrian golden hamsters

The effects of a cholesterol-free diet, a cholesterol-free diet supplemented with sesamin, and a diet supplemented with sesamin on pancreatic carcinogenesis of N-nitrosobis(2-oxopropyl) amine (BOP) were investigated in 140 female Syrian golden hamsters. BOP (70 and 20 mg/kg body wt) was injected s.c. twice at an interval of 2 weeks at the beginning of the experiment. Starting 3 weeks thereafter, the animals were maintained on basal diet, cholesterol-free diet, basal diet plus sesamin, or cholesterol-free diet plus sesamin for a further 15 weeks. All surviving hamsters were killed at week 18, and the pancreatic tissues examined histologically. The incidences of pancreatic neoplastic and preneoplastic lesions in each group did not show any statistically significant variation. The cholesterol-free diet significantly decreased the cholesterol contents of the serum, pancreas and liver, and sesamin supplement significantly decreased the cholesterol contents of the serum and liver. Both the cholesterol-free diet and sesamin decreased the serum lipoperoxide levels. The results thus indicated that low cholesterol per se and sesamin exert no significant influence on BOP-initiated pancreatic carcinogenesis in hamsters, at least within the 4 month period after carcinogen treatment.