Formation of DNA adducts from N-acetoxy-2-acetylaminofluorene and N-hydroxy-2-acetylaminofluorene in rat hemopoietic tissues in vivo.

Administration of [ring-3H]-N-acetoxy-2-acetylaminofluorene (10 mg/kg i.v.) to male F344 rats resulted in substantial binding of [ring-3H]-N-acetoxy-2-acetylaminofluorene to DNA isolated from bone marrow [20.3 +/- 1.7 (SD) pmol/mg DNA] and spleen (23.6 +/- 5.8 pmol/mg DNA) compared to liver (39.4 +/- 2.1 pmol/mg DNA) and kidney (27.1 +/- 1.0 pmol/mg DNA) 2 h after dosing. High-performance liquid chromatography analyses of trifluoroacetic acid hydrolyzed DNA from bone marrow and spleen revealed the presence of N-(guanin-8-yl)-2-aminofluorene as the major adduct comprising more than 80% of total adducts, while N-(guanin-8-yl)-2-acetylaminofluorene and ring opened derivatives of N-(guanin-8-yl)-2-aminofluorene were only minor adducts. Dose dependent binding of [ring-3H]-N-hydroxy-2-acetylaminofluorene (N-OH-AAF) to DNA and formation of individual adducts in spleen and bone marrow was observed at a dose range of 1.0-10.0 mg/kg. There was a 3- and 6-fold more DNA adduct formation in bone marrow and spleen, respectively, following treatment with [ring-3H]-N-acetoxy-2-acetylaminofluorene compared to N-OH-AAF. However, the pattern of DNA adducts formed was similar. Pretreatment of rats with the cytotoxic agent 5-fluorouracil (150 mg/kg i.p.), which causes transient depletion of hemopoietic cells, on days -10, -7, -4, -2, and -1 prior to the administration of [ring-3H]-N-OH-AAF (10 mg/kg) on day 0 resulted in different levels of N-OH-AAF binding to spleen and bone marrow DNA without altering the pattern of DNA adducts compared to that in control animals. These data suggest a possible existence of a target cell population for N-OH-AAF and perhaps other aromatic amines and amides in both bone marrow and spleen of F344 rat.