Measurement of unscheduled DNA synthesis on alkylating carcinogens in rat intestinal mucosal cells from different sites.

Abstract

Unscheduled DNA synthesis (UDS) induced by in vitro exposure to five alkylating carcinogens was measured in the mucosal cells from three different sites of the rat intestine. The yield of UDS by N-methyl-N'-nitro-N-nitrosoguanidine or N-ethyl-N'-nitro-N-nitrosoguanidine or methylazoxymethanol acetate was higher in the cells of colon & rectum than in those of the jejunum or ileum. Conversely, UDS induction by N-methyl-N-nitrosourea or methyl-methanesulphonate was seen at a rather higher level in the cells from the small intestine compared with those from the colon & rectum.