Tumor promotion by fecapentaene-12 in a rat colon carcinogenesis model

Fecapentaenes are a group of fecal mutagens produced by anaerobic microflora of the colon. The potential of fecapentaene-12 (FP-12) to promote tumor development was tested in a rat colon carcinogenesis model using N-methyl-N-nitrosourea (MNU) as the initiating agent. Two groups of female F-344 rats were initiated by intrarectal instillations of MNU (2 mg in 0.5 ml H 2 O, 3 times a week, for 3 weeks; MNU and MNU+FP-12 groups). Two additional groups (FP-12 and Control) were given H 2 O without carcinogen. In the post-initiation phase, rats of the MNU+FP-12 and FP-12 groups were intrarectally administered 400 ng of FP-12 in 0.5 ml T-E buffer, twice a week, for 24 weeks, whereas the MNU and Control groups received the vehicle only