Carcinogenic benzo(a)pyrene metabolites bound to DNA: metabolic formation by human cultured lymphocytes and by human liver microsomes.

Sonicates of human cultured lymphocytes metabolize (benzo(a)pyrene to at least two intermediates that bind covalently to deproteinized DNA in vitro. The major peak represents the 4,5-oxide bound to nucleoside(s). No correlation is found between 'aryl hydrocarbon hydroxylase activity' (or its inducibility) and benzo(a)pyrene metabolites generated by human lymphocytes and bound to DNA in vitro. Human liver microsomes produce in vitro at least six such reactive intermediates which, bound to deproteinized DNA nucleosides, are separable by chromatography. The major peak represents the 7,8-diol-9,10-epoxides bound to nucleoside(s): this highly reactive intermediate is believed to be one of the ultimate carcinogenic forms of benzo(a)pyrene.