Relationship between coronary flow and adenosine triphosphate production from glycolysis and oxidative metabolism

The relationship between coronary flow and adenosine triphosphate ATP production was determined in isolated rat hearts and in situ pigs hearts. The major source of ATP in ischemic hearts was oxidative phosphorylation. Oxidation of glucose accounted for most of the residual oxygen consumption in ischemic hearts when the concentration of fatty acids was low, but at 1.2 mM palmitate fatty acids were oxidized in preference to carbohydrate, as in aerobic hearts. The rates of ATP production from both glycolysis and oxidative metabolism were decreased in proportion to the reduction in coronary flow in oxygen-deficient hearts. Glycolysis was reduced to below aerobic rates when coronary flow was about 0.5 ml/min/g tissue in both rat hearts perfused with bicarbonate buffer and blood-perfused pig hearts. Tissue level of high energy phosphates reflected the rates of ATP production and declined in proportion to the reduction in coronary flow. In addition, tissue lactate and H+ accumulated in proportion to the restriction in flow.