Dimethylnitrosamine adducts excreted in rat urine.
Rats were injected with [14C]dimethylnitrosamine and urine was collected up to 5 days after the injection. Urine samples were concentrated and subjected to Sephadex G-10 chromatography. Three peaks of radioactivity (I-III, in the order of elution) were observed for all injection times. The peaks were analysed further by cation exchange and thin-layer chromatography and by phase-separation (pH-determination). The pK-determinations and the chromatographic properties suggested that Sephadex fraction I composed of methylated amino acids, such as N-acetyl-S-methylcysteine, 1-methylhistamine and S-methylcysteine, in addition to radioactive methionine. Sephadex fraction II was suggested to compose of allantoin and of a metabolite of thiazolidine-4-carboxylic acid. The latter compound was a reaction product of formaldehyde and cysteine, indicating activity of the formaldehyde moiety released from dimethylnitrosamine. By gel filtration properties Sephadex fraction III indicated identity as 7-methylguanine. Although the urinary radioactivity accounted for about 9% of the applied dose.
D000818:Animals; D001711:Biotransformation; D002250:Carbon Radioisotopes; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D004128:Dimethylnitrosamine / Q000652:urine*; D007700:Kinetics; D051381:Rats; D011919:Rats, Inbred Strains
D002250:Carbon Radioisotopes; D004128:Dimethylnitrosamine