[Influence of the rhythm and route of 1,2-dimethylhydrazine administration on its carcinogenic effect in mice].

Effects of route of administration (subcutaneous, intraperitoneal, by stomach tube and with drinking water) and dose fractionation on the carcinogenicity of 1,2-dimethylhydrazine (DMH) were studied in CBA and (C57B1/6j X CBA)F1 mice. Fractionation of DMH dose given subcutaneously exerted different effects on tumors at various sites: decrease of colon and anal tumor incidence, increase of vascular liver tumors and renal adenomas and no influence on hepatoma, lung adenoma and uterine sarcoma induction. When given with drinking water, DMH did not induce colon and anal tumors but produced high incidence of vascular neoplasms.

[Effect of age, castration and pregnancy on carcinogenesis, induced by 1,2-dimethylhydrazine, in CBA mice].

Subcutaneous injection of 1,2-dimethylhydrazine into female CBA mice once a week resulted in the development of tumours of the colon, anal region, uterus and liver. In 12-13-month-old mice treated with DMH an earlier appearance (week 8) of uterine sarcomas and more rapid increase in the incidence of tumours of the anal region were noted as compared to 3-month-old mice. In pregnant females treated with DMH a statistically significant decrease in the uterine sarcoma incidence was observed (10.

Non-epithelial uterine tumours induced in CBA mice by 1,2-dimethylhydrazine.

In CBA mice treated with weekly subcutaneous injections of 1,2-dimethylhydrazine an unusually high incidence of uterine sarcomas was observed in two successive experiments. The tumours are easily transplantable. The description of their histological structure is presented and their histogenesis is discussed.

[Tumors in CBA line mice caused by 1,2-dimethylhydrazine].

Female CBA mice were treated weekly with subcutaneous injections of 1,2-dimethyl-hydrazine (8 mg/Kg b. w.) for 38--40 weeks.