MUTAGENICITY OF N-OH-MOCA 4'-HYDROXYLAMINO-BIS-3,3'-DICHLORODIPHENYLMETHANE) AND PBQ (2-PHENYL-1,4-BENZOQUINONE) IN HUMAN LYMPHOBLASTOID-CELLS

The genotoxic potential of two occupationally significant chemicals, 4 ,4'-methylene-bis-2-chloroaniline (MOCA) and 2-phenyl-1,4-benzoquinone (PBQ), was explored by monitoring the induction of mutations at the H PRT locus of AHH-1 human lymphoblastoid cells. Exposure of AHH-1 cells to the putative carcinogenic metabolite of MOCA, N-OH-MOCA, induced a 6-fold increase in mutant frequency and resulted in base pair substit utions primarily at A:T base pairs. In contrast, exposure to PBQ did n ot result in an increased mutant frequency although this compound was significantly more cytotoxic than N-OH-MOCA at equimolar doses. The in duction of mutations at A:T sites by N-OH-MOCA is consistent with the type of DNA damage known to be produced by MOCA and provides a specifi c marker of genotoxic damage for exposed populations. (C) 1998 Elsevie r Science Ireland Ltd. All rights reserved.