Formation and persistence of DNA adducts in rats following intraperitoneal administration of 1,8-dinitropyrene

DNA adduct formation was examined in rat tissues following a single i.p. injection with 1,8-dinitropyrene (1,8-DNP). A single common adduct was observed in mammary, mesentery, bladder, lung, kidney and liver tissue using the 32P-postlabelling technique. Adduct levels were highest in mammary and mesentery tissue. The mammary gland and soft tissues of the peritoneal cavity are primary tumour sites in rats injected i.p. with 1,8-DNP. Adducts were not detected in the small intestine, heart or reproductive tissue. Pretreatment of rats with Aroclor 1254, an inducer of hepatic oxidative enzymes, did not alter qualitative or quantitative aspects of adduct formation. Over a 2 week period the relative adduct labelling values declined in all tissues. The loss of DNA adducts was biphasic, with an initial rapid decrease followed by a slower rate of adduct removal.