DT-DIAPHORASE AFFECTS THE MUTAGENIC ACTIVITY OF PYRENE 1,6-QUINONE INCHINESE-HAMSTER EPITHELIAL LIVER (CHEL) CELLS

The mutagenic potential of pyrene 1,6-quinone (P 1,6-Q) has been studi ed in a wide range of in vitro genetic assays including the use of mam malian cell lines. P 1,6-Q has been shown to induce gene mutations and micronuclei in V79 cells, whereas, in Chinese hamster epithelial live r (CHEL) cells, a cell line which retains activities of various xenobi otic-metabolising enzymes, a non-specific pattern of structural and nu merical chromosomal aberrations has been observed. In this study, me h ave evaluated the mutagenic activity of P 1,6-Q on V79 and CHEL cells both with and without dicoumarol, a potent inhibitor of DT-diaphorase. In V79 cells, dicoumarol (100 mu M) did not affect the mutagenic resp onse, whereas in CHEL cells, the mutation frequency significantly incr eased. This suggests that DT-diaphorase, which is expressed in liver c ells at high levels, has a possible role in the detoxification off 1,6 -Q to redox-stable hydroquinone.