[Comparison of myocardial metabolic effects of in subendocardial and subepicardial layers ischaemia and beta-adrenergic stimulation (author's transl)].

The influence of beta-adrenergic stimulation on myocardium carbohydrate and lipid metabolism has been compared with the influence of ischemia in anesthetized dog heart in situ. Transmural samples necessary to the repeated determination of tissular substrates were taken from left ventricular wall according to the "drill biopsy" technique: they were made possible by a total cardiopulmonary by-pass system. The beta-adrenergic stimulation was obtained by infusion of isoproterenol (1 microgram/kg/min.) and the ischemia by injection into left coronary artery before its division of a viscous mixture, reducing coronary flow by 40 to 70%. In both subendocardial and subepicardial layers, but mainly in the former: --beta-adrenergic stimulation lowers glycogen content and raises lactate content immediately, lowers free fatty acid concentration more progressively without modifying triglyceride concentration significantly; --ischemia decreases glycogen content and increases lactate content in the same way, but raises free fatty acid and triglyceride concentration. Consequently, beta-adrenergic stimulation and ischemia are likely to add their effects on anaerobic glycolysis, whereas they exert an opposite influence on lipid metabolism.