| Abstract: | The binding of AABP4'F and ABP4'F residues to rat liver and kidney DNA in vivo was studied at different periods of time after administration of N-G-3H]hydroxy-AABP4'F at dose levels of 5 and 25 mg/kg body weight. DNA preparations from both organs were hydrolyzed enzymatically at pH 8--9 with mixtures of DNAase, snake venom phosphodiesterase and alkaline phosphatase from Escherichia coli. The enzymatic digests were analysed by Sephadex LH-20 chromatography using synthetic N-(G-14C] deoxyguanosin-8-yl)-AABP4'F as marker. Elution with 30% ethanol gave three major peaks of tritium activity. The first peak consisted largely of N-(deoxyguanosin-8-yl)-ABP4'F decomposition products, which were not further characterized. The second product has similar chromatographical and chemical properties as 3-(deoxyguanosin-N2-yl)-AAF; and was also persistent in liver as well as in kidneys. The third peak of tritium activity co-chromatographed with the marker compound N-(G-14C] deoxyguanosin-8-yl)-AABP4'F. Kinetic studies revealed that the latter product was removed rapidly from liver and kidney DNA at equal rates (t1/2 = 2 days). Approximately 80% of the total radioactivity bound to DNA consisted of deacetylated material, which was removed at a much slower rate (t1/2 = 10 days) in both organs. An initial rapid removal of all products in kidney during the first 7 days (t1/2 = 3.3 days) at dose levels of 25 mg/kg is probably due to toxic effects on the kidneys, because this phenomenon was not observed at dose levels of 5 mg/kg. The synthetic ester N-OSO3K-AABP4'F was at least twice as reactive towards L-methionine and guanosine as compared to the corresponding AABP derivative, but had 40% of the reactivity of N-acetoxy-AAF under similar conditions. The new compounds 3-methylmercapto-4-acetylamino-4'-fluorobiphenyl and N-(deoxyguanosin-8-yl)-4-acetylamino-4'-fluorobiphenyl have been characterized by means of their NMR and mass spectra. Attempts to devise an unambiguous synthesis for 3-(deoxyguanosin-N2-yl)arylamides have been unsuccessful. |
