Effect of dibutyltin dichloride on incidence of pancreatic adenocarcinoma induced in hamsters by a single dose of N-nitrosobis(2-oxopropyl)amine.

The effects of timing of a single intragastric application of dibutyltin dichloride, at a dosage of 30 mg/kg body wt, on N-nitrosobis(2-oxopropyl)amine (BOP)-induced pancreatic carcinomas have been studied in female Syrian golden hamsters. Dibutyltin dichloride, which has been shown to produce selected bile duct injury, was administered either 1 week before or 1 week after a single injection of BOP (20 mg/kg body wt). Control hamsters were injected with BOP alone or were given dibutyltin dichloride alone. The incidence of ductal adenocarcinomas strikingly decreased in hamsters when dibutyltin dichloride was ingested after BOP treatment, but remained unaffected when dibutyltin dichloride was given before carcinogen treatment. Two cases of sarcoma were observed in the group treated with dibutyltin dichloride before BOP injection. The incidence of insulomas, which were considered as spontaneous tumors, was not influenced by dibutyltin dichloride. These results showed that intragastric application of dibutyltin dichloride after BOP treatment significantly reduced the induction of pancreatic cancer. These findings do not support speculations based on epidemiologic studies as to a promoting effect of cholestasis.