[Succinate dehydrogenase activity of isolated myocardial mitochondria during chronic insufficiency].

Succinic dehydrogenase (SDH) activity of the isolated mitochondria myocardial cells in chronic cardiac insufficiency was studied experimentally. The highest SDH values were found in the mitochondria of condensed type. The activity of the enzyme was low in the ordinary (orthodox) mitochondria. The medium SDH activity was registered in the intermediary type of mitochondria. The ordinary and the intermediary types of mitochondria prevailed in the fraction under study reflecting a fall of the SDH activity in the myocardial tissue. Biochemical study of the mitochondrial fraction revealed a slight dissociation between the tissue respiration and the oxidative phosphorilation. The low SDH activity values seen to indicatate the state of overstrain of the energy-producing structures.