[Lactate dehydrogenase and malate dehydrogenase isoenzymes in the myocardium and liver of rabbits with thyrotoxicosis].

Isoenzyme spectra of lactate and malate dehydrogenases were studied by means of polyacrylamide gel disc electrophoresis in heart muscle and liver tissue of rabbits with thyreoidin toxicosis. Under conditions of thyreotoxicosis in liver tissue content of isoenzymes LDH4 and LDH5, which slowly moved to anode, was decreased; in heart muscle content of LDH2-LDH5 was also decreased. In liver tissue the relative predominance of LDH1-LDH2 was observed, in heart muscle of LDH1. Activity and isoenzyme pattern of MDH were shown to be unaltered in homogenates of the tissues in thyreotoxicosis. An aerobisation of the LDH isoenzyme spectrum together with normal content of MDH suggested that intensive aerobic oxidation of substrates of glycolytic pathway occurred in heart muscle and liver tissue of rabbits with thyreoidin toxicosis.