Metabolic fate of N-nitrodibutylamine in the rat

The metabolic fate of N-nitrodibutylamine (NO2DBA) and N-nitrobutylamine (NO2BA) was investigated in the rat. Eight N-nitramines, including glucuronides, were isolated and identified from urine of rats given NO2DBA. They were produced by omega, omega-1, omega-2 and alpha oxidations of the N-nitramine. The in vivo metabolic pattern of NO2DBA was similar to that of N-nitrosodibutylamine, except that the monodealkylated metabolite NO2BA was also isolated and characterized. When NO2BA was administered to rats, no N-nitramine other than a small amount of unchanged NO2BA was identified in the urine. Besides N-nitramines, N-acetyl-S-(butyl, 3-oxobutyl and 3-hydroxybutyl)-L-cysteines were isolated and identified (as their methyl esters) from the urine of rats given both NO2DBA and NO2BA. The relative ratio of these three L-cysteine derivatives obtained from NO2DBA was quite similar to that from NO2BA, indicating that NO2DBA produces in vivo a chemical species with butylating ability through NO2BA.