Induction by dimethylhydrazine of intestinal carcinoma in normal rats and rats fed high or low levels of vitamin A
Rogers, A.E.; Herndon, B.J.; Newberne, P.M.
Cancer Research 33(5): 1003-1009
1973
ISSN/ISBN: 0008-5472 PMID: 4703115 Document Number: 67158
Male CD Sprague-Dawley rats were fed to appetite on a semisynthetic diet which lacked vitamin A or was supplemented with retinyl palmitate to provide 30 or 500 IU vitamin A/g diet. Administration by gastric tube of 1,2-dimethylhydrazine (DMH) dissolved in 0.9% NaCl solution induced intestinal carcinoma in 60 to 100% of the rats within 6 months. In rats given the deficient diet for 6 to 8 weeks and then a supplement containing vitamin A, 1 IU/g, for periods of 1 to 3 days as needed to prevent weight loss and death, chronic deficiency of vitamin A increased the incidence of tumours slightly and seemed to reduce induction time. The larger amount of dietary vitamin A, which was sufficient to raise the vitamin content in serum and reduce growth, did not change the incidence of colon tumours but decreased the number of tumours found with the highest dose of DMH.