Studies of practolol on mitochondrial metabolism

The possible effect of practolol (ICI 50,172) on mitochondrial metabolism was studied. The drug inhibited the oxidation of glutamate, alpha-ketoglutarate and succinate by heart mitochondria. The polarographic determinations showed that practolol is an inhibitor of the oxidative phosphorylation. The activity of NADH-oxidase, NADH-ferricyanide reductase, NADH-cytochrome c redutase was inhibit by the drug; no effect was observed on the succinate dehydrogenase. The electron microscopy of isolated mitochondria treated with practolol showed that the drug promote conformational changes of the mitochondrial membrane, probably concerning with the detergent characteristics of the drug.