Distribution of glycogen and lipids in the ischemic canine left ventricle: biochemical and light and electron microscopic correlates.

Transmural gradients in the contents of glycogen triglycerides, and phospholipids were studied in the dog left ventricle with and without 4 hours of left circumflex artery ligation. In control dogs (patent circumflex), an increasing outer to inner glycogen gradient was observed. After 4 hours of ischemia, subepicardial glycogen content was similar to control values, but midventricular and subendocardial stores were nearly depleted, thus indicating a reversal of the control gradient. These changes were seen biochemically as well as by light and electron microscopic techniques. In the present studies, conclusive evidence for a transmural gradient in tissue triglyceride content was not obtained in either control or ligated dogs. However, an approximate three-fold increase in midventricular and subendocardial triglycerides was observed in ischemic hearts. Regional contents of total tissue phospholipids appeared to be similar across the left ventricular wall in both normal and ischemic left ventricles.