[Effect of the duration of administration of 1,2-dimethylhydrazine on its carcinogenic effect]

The (CBA x C57Bl)F1 female mice were treated with weekly injections of 1,2-dimethylhydrazine (DMH) at a dose rate of 4.15 mg/kg of body weight during different time periods. Relations between the incidence of organ specified particular tumours depend on the total DMH dose. Incidence of haemoblastoses decreases with an increase in the DMH dose. Dose relationships of the tumour incidence are analyzed statistically by the method with intercurrent mortality corrections and carcinogen effect expressed by relations of the observed and expected numbers.