Effect of rhythm of administration of 1,2-dimethylhydrazine on its carcinogenic activity

Abstract

The rhythm of injection of 1,2-dimethylhydrazine (DMH), in the same total dose, affects the ultimate carcinogenic effect. The most widespread development of intestinal tumors is observed if DMH is given once a week in a dose of 21 mg/kg body weight. Daily injection in a dose of 3 mg/kg leads to less marked tumor development, limited to the large intestine. However, under these conditions pronounced degenerative and necrobiotic, and in a few cases neoplastic changes develop in the liver. The frequent administration of small doses of the carcinogen leads to a marked decrease in the cytochrome P₄₅₀ content in the microsomes of the liver; this evidently delays the metabolism of DMH, its conversion into its end product, and binding of the latter with macromolecules of the enterocytes.