Identification of glutathione conjugates formed from N-hydroxy-2-acetylaminofluorene in the rat.

Rats which had received N-hydroxy-2-acetylaminofluorene (N-OH-AAF) excreted two glutathione conjugates in the bile. Pretreatment with the sulphotransferase inhibitor pentachlorophenol reduced the amounts excreted by 50% suggesting that these conjugates were formed in vivo from the highly reactive N-O-sulphate ester of N-OH-AAF (AAF-N-sulphate). In order to identify these biliary conjugates synthetic GSH conjugates were prepared by the reaction of N-acetoxy-AAF, (a model compound for AAF-N-sulphate), with GSH. Four conjugates were isolated and characterized by ultraviolet, proton magnetic resonance, mass spectroscopy and by the determination of their amino acid composition. These conjugates were identified as 1-, 3-, 4- and 7-(glutathion-S-yl)-N-acetyl-2-aminofluorene, respectively. The two biliary conjugates were identified as 1- and 3-(glutathion-S-yl)-N-acetyl-2-aminofluorene.