title: Chronic toxicity of sodium nitrite in mice, with reference to its tumorigenicity.
abstract: Sodium nitrite has been widely used as one of the most effective food additives to tinge color on cured meat. However, it has been elucidated that this chemical is not merely a precursor of N-nitroso compounds, many of which are strongly carcinogenic, but also a mutagenic substance in biological tests. In order to ascertain the possible tumorigenicity of sodium nitrite itself, chronic toxicity of the agent in mice, by means of daily oral administration as drinking water for more than 18 months, in the concentration of 0.5 (maximum tolerated dose), 0.25, and 0.125%, was tested. As a result, development of various tumors, including thymic lymphoma, nonthymic lymphoid leukemia, pulmonary adenoma and carcinoma, and benign and malignant tumors in soft tissue, was seen in these mice. However, as to the incidence of tumors as well as the developmental time of each histologically classified tumor, no apparent difference was detected between those in the experimental groups and the control group.
mesh_terms: D000818:Animals; D002273:Carcinogens; D005260:Female; D007938:Leukemia / Q000139:chemically induced; D008113:Liver Neoplasms / Q000139:chemically induced; D008175:Lung Neoplasms / Q000139:chemically induced; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced; D051379:Mice; D008813:Mice, Inbred ICR; D009573:Nitrites / Q000633:toxicity*; D012977:Sodium Nitrite / Q000633:toxicity*; D012983:Soft Tissue Neoplasms / Q000139:chemically induced; D013953:Thymus Neoplasms / Q000139:chemically induced; D013997:Time Factors; D014594:Uterine Neoplasms / Q000139:chemically induced
chemical_list: D002273:Carcinogens; D009573:Nitrites; D012977:Sodium Nitrite