Modification of pancreatic carcinogenesis in the hamster model. XI. Inhibitory effect of pilocarpine hydrochloride.

Pilocarpine hydrochloride (PH) was administered as a single sc injection (15 mg/kg body wt) to outbred Syrian golden hamsters either prior to, simultaneously with, or after a single 20-mg/kg body weight dose of the pancreatic carcinogen N-nitrosobis(2-oxopropyl)amine (BOP). An additional group was treated with PH, once before and once simultaneously with BOP; another group received PH daily for life after BOP and controls were given BOP only. Surviving hamsters were killed 46 weeks after BOP treatment. PH significantly inhibited pancreatic ductal-ductular cancer induction, whether it was given once before, simultaneously with, or after BOP. A more pronounced inhibitory effect was seen when PH was administered once before and once simultaneously with BOP. However, daily injection of PH did not alter the carcinoma incidence over the BOP control value. The possible mechanisms are discussed.