Metabolic fate of N-butyl-N-(4-hydroxybutyl) nitrosamine and N, N-dibutylnitrosamine in the guinea pig, with reference to their carcinogenic effects on the urinary bladder.

The metabolic fate of two urinary bladder carcinogens, N-butyl-N-(4-hydroxy-butyl) nitrosamine (BBN) and N-N-dibutylnitrosamine (DBN), was studied in the guinea pig, in order to elucidate species differences of response to these N-nitrosamines in this animal species and the rat. Based on the urinary metabolites characterized after oral administration of these compounds, the metabolic pathways of BBN and DBN in the guinea pig were shown to be essentially similar to those in the rat. The principal urinary metabolite of BBN and DBN in the guinea pig, however, was not N-butyl-N-(3-carboxypropyl) nitrosamine (BCPN), as was the case in the rat, but the glucuronic acid conjugate of BBN and that of N-butyl-N-(3-hydroxybutyl) nitrosamine, respectively. The species variation in response to BBN and DBN as bladder carcinogens in these animals is discussed on the basis of the urinary excretion of BCPN.