Evidence of formation of N-methyl-N-nitrosourea in rats given n-methylurea and sodium nitrite

✍ Scribed by Ruggero Montesano; P. N. Magee

• Publisher: John Wiley and Sons
• Year: 1971
• Tongue: French
• Weight: 540 KB
• Volume: 7
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.2910070208

✦ Synopsis

Abstract

N[^14^C]‐methylurea and sodium nitrite were administered simultaneously to rats by stomach tube in order to demonstrate methylation of the nucleic acids due to the formation in the stomach of the corresponding nitrosamide, N[^14^C]‐methyl‐N‐nitrosourea. The ion‐exchange chromatograms of the hydrolysates of stomach, liver and small intestine nucleic acids show a radioactive peak corresponding to the altered base 7‐methylguanine in the rat receiving N[^14^C]‐methylurea and sodium nitrite. No evidence of 7‐methyl‐guanine was obtained when N[^14^C]‐methylurea was administered alone. These findings are interpreted as indicating that the highly potent carcinogen N‐methyl‐N‐nitrosourea is formed in the stomach as a result of the nitrosation of the corresponding secondary amide and absorbed into the circulation of the rat. The possible consequences of the in vivo formation of carcinogenic N‐nitroso compounds in the aetiology of cancer are discussed.