The effect of streptozotocin and a high-fat diet on BOP-induced tumors in the pancreas and in the submandibular gland of hamsters bearing transplants of homologous islets.

The effect of a high-fat diet (HF) and streptozotocin (STZ) was investigated in the rapid cancer induction model developed in our laboratories. Syrian golden hamsters bearing homologous islets transplanted in their right submandibular gland (SMG) received a HF or a low-fat diet (LF). Half of the animals from each dietary group received STZ (HF-STZ and LF-STZ groups) and the other half did not (HF and LF groups). One week later, all hamsters were treated with N-nitrosobis(2-oxopropyl)amine (BOP) weekly for 3 weeks and the experiment was terminated 12 weeks after the last BOP injection. Pancreatic lesions were found in many hamsters, with a lower incidence in the LF-STZ group (13%) than in other groups (35-45%). A HF diet counteracted the inhibitory effect of STZ on pancreatic tumor induction by yet unknown mechanisms. SMG tumors, all ductal-type adenocarcinomas, developed in all groups and the incidence was lowest in the HF group (6%) compared to the LF group (15%), LF-STZ group (17%) and HF-STZ group (18%). However, the difference was not statistically significant. It was concluded that a HF diet counteracts the inhibitory effect of STZ on BOP-induced pancreatic lesions but has no effect on the induction of tumors in the SMG. STZ pretreatment does not influence tumor induction of the SMG of these hamster.