Covalent protein binding of reactive adriamycin metabolites in rat liver and rat heart microsomes.

Covalent binding of 3H-labeled adriamycin metabolites to bovine serum albumin and microsomal protein is demonstrated in an aerobic incubation system with rat liver and rat heart microsomes, respectively, using exhaustive organic solvent extraction and gel chromatography. Covalent protein binding was dependent on active microsomes, NADPH, and oxygen and was inhibited by reduced glutathione and other sulfhydryl compounds. The anthracycline moiety was spectrophotometrically evidenced in the adriamycin metabolite(s) covalently bound to protein. Thus, enzymatic activation of adriamycin in the heart with consecutive covalent protein binding of reactive adriamycin semiquinone radicals may contribute to adriamycin cardiotoxicity.