Increased renal carcinogenesis by dimethyl nitrosamine in protein deficient rats.

Protein deficiency at the time of dosage protects rats against the acute lethal effects of dimethyl nitrosamine, but increases the late carcinogenic actions of the poison. A single dose of 60 mg. dimethyl nitrosamine/kg. leads to the development of kidney cancers in all the surviving rats after 8-11 months. 40 mg./kg. produces tumours in over half of the survivors in 14 months. Induction of liver microsomal hydroxylation enzymes with phenobarbitone does not prevent the carcinogenic effects of dimethyl nitrosamine.