The covalent interaction of 1,4-dibromobenzene with rat and mouse nucleic acids: in vivo and in vitro studies.

1,4-Dibromobenzene (1,4-DBB) was covalently bound to DNA from liver, kidney, lung and stomach of mice after intraperitoneal administration. The covalent binding index (CBI) value (23 in mouse liver) was typical of weak initiators. On the contrary, no interaction with DNA from rat organs was observed (CBI detection limit: 1.3-2.6). The in vitro interaction of 1,4-DBB with calf thymus DNA was mediated mainly by microsomes, especially those from liver of both species and from mouse lung. Mouse subcellular fractions were more active then rat subcellular fractions. Unlike liver cytosol, subcellular cytosolic fractions from lung, kidney and stomach were capable of bioactivating 1,4-DBB, although to a lesser extent than liver microsomes. Both cytochrome P-450 and GSH-transferases are involved in 1,4-DBB bioactivation.