Comparison of oxidant activities and the activation of benzo(a)pyrene-7,8-dihydrodiol by polymorphonuclear leucocytes from human, rat and mouse.

1. Polymorphonuclear leucocytes (PMNs) from human, mouse and rat were compared for their ability to activate benzo(a)pyrene-7,8-diol to a DNA-binding intermediate and a chemiluminescent dioxetane derivative. 2. Human PMNs activated benzo(a)pyrene-7,8-diol to the greatest extent, which correlated with their rate of superoxide anion generation and myeloperoxidase activity relative to these activities by PMNs from mice and rats. 3. Benzo(a)pyrene-7,8-diol chemiluminescence elicited by PMNs from all three species was significantly inhibited by azide, a myeloperoxidase inhibitor. On the other hand, superoxide dismutase (SOD) was very effective in inhibiting benzo(a)pyrene-7,8-diol chemiluminescence with mouse PMNs but not human or rat PMNs. Mouse PMNs exhibited a high rate of superoxide generation but low myeloperoxidase activity, whereas rat PMNs exhibited a low rate of superoxide generation but high myeloperoxidase activity.