[Studies on the induction by extracts from airborne particulates of benzo(a)pyrene hydroxylase and the binding of benzo(a)pyrene to DNA in the rat lung in vivo after pertracheal administration (author's transl)].

A method is described for the administration of suspended material into the rat lung. The rat is narcotized by CO2/air, the trachea is punctured and the suspension is sucked into the lung by the inhaled air (pertracheal administration, p. t. a.). BaP administered by this method is eliminated from the lung rapidly, while metabolites persist for a longer period. The radioactivity detected in the blood can be attributed predominantly to metabolites, a small fraction is unmetabolized benzo(a)pyrene. The activity of benzo(a)pyrene hydroxylase is induced in the lung after p. t. a. of extracts from airborne particulate matter. The activity increases depending on the dose until a plateau of activity is reached at high doses. Pertracheally administered BaP is bound to DNA of the lung. Pretreatment with extracts p.t.a. enhances the binding. After enzymatic digestion of DNA BaP-nucleoside adducts are detected by HPLC. According to data published in the literature to adducts are supposed to be derived from BaP-phenols and BaP-diolepoxides. It is concluded tht the components of airborne particulates can modify the activity of metabolizing enzymes and increase the rate of formation of adducts in the lung in vivo.