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N-Nitroso-N-methylurea

N-Nitroso-N-methylurea (MNU) is a highly potent carcinogen, mutagen, and teratogen. MNU is an alkylating agent, and exhibits its toxicity by transferring its methyl group to nucleobases in nucleic acids.

Acute exposure to MNU in humans can result in skin and eye irritation, headache, nausea, and vomiting.^[1] MNU is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals (IARC 1972, 1978, 1987).^[2] Various cancers induced in animal models include: squamous cell carcinomas of the forestomach, sarcomas and gliomas of the brain, adenocarcinomas of the pancreas, leukemia, and lymphomas.^[2] However, the actual potential for human exposure is quite limited, as the chemical is not produced or used in large quantities ^[2]

MNU is teratogenic and embryotoxic, resulting in craniofacial (cleft palate) and skeletal defects, increased fetal resorption, and fetal growth retardation.^[3][4][5] Exposure to MNU during pre-implantation, post-implantation, organogenesis, or by paternal exposure can result in these effects.

References

1. ^ Hazardous Substance Fact Sheet for MNU New Jersey Department of Health and Senior Services
2. ^ ^{a b c} MNU Substance Profile NTP, Report on Carcinogens, Eleventh Edition
3. ^ Wada, A., et al. (1994). Induction of Congenital Malformations in Mice by Paternal Methylnitrosourea Treatment. Congenital Anomalies 34:65-70.
4. ^ Nagao, T., et al. (1991). Induction of Fetal Malformations After Treatment of Mouse Embryos with Methylnitrosourea at the Preimplantation Stages. Teratogenesis, Carcinogenesis, and Mutagenesis 11:1-10.
5. ^ Faustman, E., et al. (1989). In Vitro Developmental Toxicity of Five Direct-Acting Alkylating Agents in Rodent Embryos: Structure-Activity Patterns. Teratology 40:199-210.