ADENOCARCINOMA PRODUCTION IN RATS ADMINISTERED 1,2-DIMETHYLHYDRAZINE AND FED IRON SALT AND GUAR GUM DIETS

Iron salts supplemented in a basal ratio, were fed to young Sprague-Da wley male rats for prolonged periods and the frequency of colonic aden ocarcinomas induced by repeated s.c. injection of 1,2-dimethylhydrazin e (DMH) at unit base doses of 9.0 mg/kg, ascertained and compared with the respective controls. In a series employing ferric ammonium citrat e (0.46% Fe), in addition to ferrous sulfate (0.11% Fe) and ferric amm onium sulfate (0.12% Fe), DMH injection was started on day 15 and the animals necropsied 22 weeks after the last of 23 doses. The general co ndition was more involved with the 0.46% Fe diet and the total colonic lesion numbers were in the control range. However, the ferric ammonui um sulfate-fed group showed a significant increase in tumors in the di stal colon portion. In the second experiment, 15% guar gum as such and in admixture with ferric ammonium sulfate (0.12%) were compared with the respective controls, the first of 20 weekly dosages of DMH being a dministered on day 28 of the feeding. At 32 weeks following injection l, the overall lesion differences were not remarkable, but the guar gu m ratios engendered decreases in the distal colon tumor frequencies. I n general, lesion incidence was extensive, involving 80-100% of the an imals per group of the 2 series. Adenocarcinomas occurred in the small intestine and were more prominent in the control and 15% guar gum die tary groups but fewer with the ferric ammonium sulfate supplement.