Carcinogenic activity of N-nitrosodiethylamine in snakes (Python reticulatus, Schneider).

Fourteen snakes of the species Python reticulatus were randomized after one year's adaptation in our laboratory, i.e., at the age of 18 months. Groups of three animals (average body weight, 1 kg) were subjected to lifelong administration of 24, 12 or 6 mg/kg body weight of N-nitrosodiethylamine (NDEA) at fortnightly intervals. The NDEA-containing aqueous solution (0.3 ml/kg body weight) was administered by gavage. Five untreated animals served as controls. Snakes receiving 24 mg/kg NDEA died from toxic liver and kidney damage within the first year of experimentation. The three snakes receiving 12 mg/kg NDEA died within the last three months of the second year of treatment. These animals had developed multiple benign and malignant tumours in the liver and the kidney. The two animals that died last also developed tumours in the oral cavity and the trachea. Animals treated with 6 mg/kg NDEA died from tumours in the trachea.