Trimethylhydrazine hydrochloride as a tumor inducer in Swiss mice.

A 0.05% solution of trimethylhydrazine hydrochloride (TMH) administered for a lifetime in drinking water to outbred Swiss albino mice, beginning at 6 weeks of age, induced tumors of blood vessels, lungs, and kidneys. The tumor incidences in these tissues in untreated controls were 5,22 and 0%, whereas in the treated groups the corresponding tumor incidences increased to 85, 44, and 6%, respectively. Histopathologically, tumors were classified as angiosarcomas of blood vessels and adenomas of the lungs and kidneys. The study thus demonstrated the tumorigenicity of TMH. Contrary to expectation, the chemical structure modification apparently failed to alter qualitatively the tumorigenic response.