The model of isolated totally ischemic rat heart perfused by physiological saline containing isadrinum was used to study the influence of superoxiddismutase (SOD) additions on the characteristics of perfusate, flowing from the heart. Isadrinum has promoted revealing the cardiotoxic effect of high catecholamine doses: the activity of lactate dehydrogenase, creatine phosphokinaze, acid phosphatase, catepsine D increased significantly in the perfusate. Concentration of middle-weight peptides (MWP) increased 1.7 times, the phospholipide level (PL) increased 2 times. These changes were combined with the abnormally high content of the POL products in the perfusate. Addition of SOD to the perfused saline decreased the activity of perfusate enzymes and the content of POL products, PL, MWP and Ca in the perfusate. It is assumed that the cardioprotective effect of SOD can be related not only to the ability of SOD to neutralize the superoxide radical, but also to the suppression of the specific adrenergic myocardium responses.