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EC number: 209-935-0 | CAS number: 598-50-5
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Description of key information
Guinea-pigs were treated with methylurea (MU) and sodium nitrite and the formation of N-nitrosomethylurea (NMU) from MU and sodium nitrite and the disappearance of NMU was analysed in the stomach. NMU was shown to be formed readily in the stomach of the guinea-pig and to be absorbed from the stomach into the blood (Yamamoto et al., 1987).
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Additional information
In the study of Yamamoto et al., 1987, guinea-pigs were treated with methylurea (MU) and sodium nitrite. The study was concentrated on the formation of N-nitrosomethylurea (NMU) from MU and sodium nitrite in the guinea-pig stomach and the disappearance of NMU from the stomach. Guinea-pigs were used since they have only glandular stomachs and the pH of the gastric juice (1-2) is similar to that of humans. NMU was relatively stable in the isolated gastric contents of this species. When NMU was injected into the pylorus-ligated stomach of fasting guinea-pigs, about 50 and 37% of the NMU remained at 20 and 30 min, respectively. Some 19 and 42% remained 30 min after NMU was given orally by stomach tube to fasting and feeding guinea-pigs, respectively. NMU was detected in most blood samples irrespective of the administration procedure, but it disappeared rapidly from the blood after i.v. injection. Nitrite disappeared rapidly from the pylorus-ligated stomach, residual nitrite being less than 20% of the dose in 2.5 min. When 7.5 µmol MU and 15 µmol NaNO2 were co-injected into the ligated stomach, 3.1 µmol NMU was detected 10 min after the injection, followed by a gradual decrease. When MU and NaNO2 were given orally to the animals, 0.7-1.0 µmol NMU was detected in the stomach 10 min after the treatment. Thus NMU was shown to be formed readily in the stomach of the guinea-pig and to be absorbed from the stomach into the blood.
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