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 invest igated in the rapid cancer induction model developed in our laboratori es. Syrian golden hamsters bearing homologous islets transplanted in t heir 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)a mine (BOP) weekly for 3 weeks and the experiment was terminated 1% wee ks after the last BOP injection. Pancreatic lesions were found in many hamsters, with a lower incidence in the LF-STZ group (13%) than in ot her groups (35-45%). A HF diet counteracted the inhibitory effect of S TZ on pancreatic tumor induction by yet unknown mechanisms, SMG tumors , all ductal-type adenocarcinomas, developed in all groups and the inc idence 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 wa s not statistically significant. It was concluded that a HF diet count eracts the inhibitory effect of STZ on BOP-induced pancreatic lesions but has no effect on the induction of tumors in the SMG. STZ pretreatm ent does not influence tumor induction of the SMG of these hamster. (C ) 1997 Elsevier Science Ireland Ltd.