Nicotinamide stimulates the repair of carcinogen-induced DNA damage in the hamster pancreas in vivo.

A single dose of nicotinamide (350 mg/kg, i.p.) given 3 hrs after a single dose of the carcinogen N-nitrosobis (2-oxopropyl) amine (BOP) (10 mg/kg, s.c.) stimulated the repair of DNA damage induced by BOP in the hamster pancreas. Damage was measured by alkaline elution 24 hrs after dosing with BOP. When given up to 1 hr before BOP nicotinamide was ineffective. This effect did not appear to be due to an alteration in the rate of unscheduled DNA synthesis which was not stimulated by nicotinamide. These data correlated positively with the inhibitory action of nicotinamide on BOP carcinogenesis in the hamster pancreas.