Effects of cardiac work on glycogen fractions of the heart

¹ Department of Physiology and Pharmacology, University of Missouri Medical Center, Columbia, Missouri

Trichloroacetic acid soluble (TCA) glycogen and residual glycogen were determined in the left ventricle and interventricular septum of hearts of unfasted male albino rats. Left ventricular hypertrophy and an elevation of blood pressure were produced in rats by coarctation of the abdominal aorta for a period of 5 days. No change in concentration of either cardiac glycogen fraction was found at the end of the 5-day coarctation period. Coarctation of the abdominal aorta for 1 hour failed to alter the glycogen fractions of the left ventricle, whereas complete ligation of the aorta for the same time interval promoted the deposition of TCA glycogen. In rats subjected to 5, 15 and 60 minutes of swimming, left ventricular glycogen was significantly depleted. Residual glycogen resynthesis was complete after 1 hour of rest from 15 minutes of exercise, and the TCA fraction was significantly increased at this time. Method of sacrifice influenced the concentration of the cardiac glycogen fractions. The above experimental procedures predominantly affected the TCA fraction of cardiac glycogen.