Carcinogenicity test of six nitrosamides and a nitrosocyanamide administered orally to rats.
Six nitrosamides [ethylnitrosourea (ENU), 2-hydroxyethylnitrosourea (HENU), carboxymethylnitrosourea, 1-nitroso-5,6-dihydrouracil (NDHU), 1-nitrosohydantoin, and N-methyl-N-nitrosobenzamide (MNB)] and ethylnitrosocyanamide (ENC) were administered chronically in sodium citrate-buffered drinking water to MRC Wistar rats. ENU induced tumors of the reticuloendothelial system (RES) (50% incidence), mammary glands, and large intestine. NDHU in drinking water produced hepatocellular carcinomas (96% incidence), but NDHU injected ip caused mostly tumors at the injection sites (54% incidence). HENU produced bone tumors (38% incidence) and RES tumors (28% incidence). ENC produced nasal cavity tumors (36% incidence). Papillomas and/or carcinomas of the forestomach, tongue, and pharynx were induced by most of the compounds, with the highest incidence in the forestomach (47% for MNB); these tumors were attributed to local action when the compounds were ingested. Carcinogenicity was not quantitatively correlated with direct mutagenicity for Salmonella typhimurium TA1535.
D000284:Administration, Oral; D000818:Animals; D001549:Benzamides / Q000008:administration & dosage / Q000633:toxicity; D002273:Carcinogens; D004353:Drug Evaluation, Preclinical; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000139:chemically induced; D006827:Hydantoins / Q000008:administration & dosage / Q000633:toxicity; D008297:Male; D012157:Mononuclear Phagocyte System; D009153:Mutagens; D009374:Neoplasms, Experimental / Q000139:chemically induced*; D009602:Nitrosamines; D009603:Nitroso Compounds / Q000008:administration & dosage / Q000633:toxicity*; D009607:Nitrosourea Compounds / Q000008:administration & dosage / Q000633:toxicity*; D051381:Rats; D012142:Respiratory Tract Neoplasms / Q000139:chemically induced; D014498:Uracil / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000633:toxicity
D001549:Benzamides; D002273:Carcinogens; D006827:Hydantoins; D009153:Mutagens; D009602:Nitrosamines; D009603:Nitroso Compounds; D009607:Nitrosourea Compounds; C011954:1-nitroso-5,6-dihydrouracil; C019505:1-nitrosohydantoin; D014498:Uracil; C019485:N-methyl-N-nitrosobenzamide