Structures of hepatic nucleic acid-bound dyes in rats given the carcinogen N-methyl-4-aminoazobenzene.

Rats were given the hepatocarcinogenic dye N-methyl-4-aminoazobenzene labeled in the prime ring with tritium. The hepatic ribosomal RNA and DNA from these rats were hydrolyzed to uoe;d imce;psode-dye products. The major nucleoside-dye derivatives cochromatographed with synthetic N-(guanosin-8-yl)-and N-(deoxyguanosin-8-yl)-N-(methyl-4-aminoazobenzene, respectively, on cellulose and silica gel thin layers in several solvent systems. Additional evidence for the characterization of the hepatic RNA-nucleoside derivative was obtained through its degradation by alkali in air to N-methyl-4-aminoazobenzene and -4-aminoazobenzene, as previously described for N-(guanosin-8-yl)-N-methyl-4-aminoazobenzene. The same nucleoside derivatives were also derived from ribosomal RNA and DNA reacted in vitro with the carcinogenic electrophilic derivative N-benzoyloxy-N-methyl-4-aminoazobenzene, esterification of the N-hydroxy derivative, and reaction of the resultant electrophilic esters with DNA and RNA.