Abstract
Comparing the atrial muscle and the ventricular muscle, the basic carbohydrate metabolism by the rabbit heart muscle was studied using the technique of the radioactive isotope tracer. In addition, the diaphragm was chosen as a control. The substrates used in the present experiments were glucose-U-C14, glucose-1-C14 and glucose-6-C14
(1) The oxygen consumption of the atrial muscle was nearly twice that of the ventricular muscle, and approximately 3 times that of the diaphragm. But there were no significant differences between the right side and the left side of the heart. These results agreed with other workers'.
(2) C14O2 converted from glucose-U-C14 was, on the whole, in the same relation as the oxygen consumption.
(3) The oxidative pentose pathway estimated by the ratio of C14O2 for carbon-1 to that for carbon-6 was found in the ventricular muscles in a fairly high amount, but none in the atrial muscle. In addition, the oxidative pentose pathway was also found in the diaphragm in the same percentage as that of the ventricular muscle.
(4) The role of the oxidative pentose pathway of the heart muscle was discussed in brief, comparing it with other tissue.
