Binding of chemicals to mouse lung DNA after pretreatment with single chemicals and complex chemical mixtures

The effects of pre-exposure to coal gas condensate (CGC), diesel exhaust extract (DEE), or selected compounds in complex chemical mixtures were investigated on the binding of chemicals to mouse lung DNA. The amount of radiolabel bound to DNA after intratracheal administration of labeled benzo[a]pyrene (BaP), 2-aminoanthracene (2-AA), phenanthridone, (PNDO), 1-nitropyrene (NP), dinitropyrenes, (DNP), or 1,3,6-trinitropyrene (TNP) was determined after pretreatment with CGC, DEE, BaP, or NP. The BaP and CGC were the most effective inducing agents. Four hours after administration of radiolabels in BaP-induced mice, amounts of [14C]-1-NP, [14C]DNP, [3H]BaP, and [3H]-2-AA bound to DNA were increased 160-, 7.6-, 5.4-, and 5.2-fold above control values. Pretreatment with CGC increased binding of [14C]-1-NP, [3H]BaP, and [3H]2-AA, 90-, 7.6-, and 2.8-fold, respectively, above control values. The amount of 1-NP bound to DNA was 30 times greater than BaP. Following induction, the average amount of label bound 1 wk after administration ranged from 43 to 62% of 4-hr-bound activity. The [14C]PNDO did not bind to DNA under the assay conditions used. The DEE pretreatment increased binding of BaP but had little effect on binding of other chemicals. The 1-NP pretreatment did not increase binding of any chemicals