Effect of dietary sodium ascorbate on 1,2-dimethylhydrazine- or methylnitrosourea-induced colon carcinogenesis in rats.

The effect of dietary sodium ascorbate (SA) on colon carcinogenesis evoked by 1,2-dimethylhydrazine (DMH) or N-methyl-N-nitrosourea (MNU) was studied in female F344 rats. Animals were fed diets containing 0, 0.25 and 1% of SA and given s.c. a single dose of 150 mg DMH/kg body wt., 10 weekly s.c. injections of 20 mg DMH/kg body wt. or intra-rectal administration of 2 mg MNU, twice a week for 2 weeks. The incidence of colon and kidney tumors was lower in rats fed the 0.25 or 1% SA and treated with a single dose of DMH than in the animals fed the diet without SA; however, the tumour incidences did not differ between the SA- and control diet-fed animals and treated with multiple doses of DMH or MNU.