Nicotinamide and selenium stimulate the repair of DNA damage produced by N-nitrosobis (2-oxopropyl) amine.

The effects of nicotinamide (NIC) and selenium (SE), given alone or together, on N-nitrosobis (2-oxopropyl) amine (BOP)-induced DNA damage were measured in rat liver and colon. SE stimulated DNA repair in both tissues, whereas NIC was without effect. The failure of NIC to stimulate the repair of BOP-induced DNA damage in rat liver, where BOP is a methylating and hydroxypropylating agent, suggested that the nature of the DNA damaging agent could be important. NIC stimulated the repair of DNA damage induced by BOP (methylating agent in the pancreas) and N-nitrosodiethylamine (ethylating agent) but not by azaserine (carboxymethylating agent) or N-nitroso-5,6-dihydrouracil (carboxyethylating agent).