Interindividual Variation in Biotransformation and Cytotoxicity of Bromobenzene as Determined in Primary Hepatocyte Cultures Derived from Monkey and Human Liver

1 Bromobenzene-evoked hepatotoxicity resulting from cytochrome P450-mediated epoxidation has been studied extensively in rodents in vivo and in rodent hepatocytes. In this paper we present data concerning the formation of bromphenols, glutathione (GSH) depletion and cytotoxicity observed in primate hepatocytes in primary culture after exposure to bromobenzene (BrB).2 After pre-incubation for 2 or 24 h, hepatocytes were exposed to BrB in concentrations up to 2 mM for 4 or 24 h.3 In both human and cynomolgus monkey hepatocytes BrB cytotoxicity and GSH depletion were found after exposure to 2 mM BrB. The degree of the observed effects was not influenced by the duration of pre-incubation and/or exposure periods.4 Major inter-individual differences were observed, which could not be attributed to differences in cytochrome P450-mediated bioactivation rates. This suggests that the variation in individual susceptibility to BrB may be related to interindividual differences in the activity of de-activating (metabolic) pathways.5 The study of the background of these interindividual differences may contribute to a more complete understanding of the factors ruling sensitivity to BrB or related chemicals.