Metabolism of simple quinones in guinea pig and rat cardiac tissue.

1. The metabolism of the benzoquinone 2,5-dimethylbenzoquinone and of the naphthoquinone 2,3-dimethoxy-1,4-naphthoquinone was studied in subcellular fractions isolated from cardiac tissue of guinea pig and rat. 2. In both species the benzoquinone was mainly metabolized through the mitochondrial NADH-ubiquinone-oxidoreductase, whereas the naphthoquinone was metabolized to approximately equal extents by mitochondrial reductase and by soluble DT-diaphorase. 3. Guinea pig heart metabolized 3 times more naphthoquinone than rat heart. 4. As a consequence of quinone metabolism, marked amounts of O2- center dot - were generated; naphthoquinone-induced O2- center dot - generation was about 4-fold higher in guinea pig than in rat heart.