Tumor ¡genesisStudies with 1,2-Dimethylhydrazine Dihydrochloride, Hydrazine Sulfate, and Isonicotinic Acid in Golden Hamsters1

Solutions of 0.012% hydrazine sulfate, 0.001% 1,2-dirnethylhydrazine dihydrochloride, and 0.5% isonicotinic acid were given continuously in the drinking water of 9-, 7-, and 5-week-old randomly bred Syrian golden hamsters for the remainder of their lifetime. The consumption of hydrazine sulfate and isonicotinic acid was without any significant carcinogenic action, while 1,2-dimethylhydrazine dihydro chloride induced angiosarcomas of the blood vessels with incidences of 89% in females and 82% in males. In addition, it produced an appreciable number of tumors in the cecum and liver. ' These findings clearly show that the carcinogenic effect of