A comparative enzyme histochemical study of glucose metabolism in the conduction system of mammalian hearts.

A histochemical study of some enzymes of glucose metabolism was performed on the heart conduction system of rat, dog, rabbit, pig, calf and lamb. Histochemical activities revealed a higher rate of anaerobic metabolism and a lower rate of aerobic metabolism in the conducting cells in comparison with the working myocardial fibres. An increase of the histochemical activities from the atrioventricular node to the distal portions of bundle branches was noted. The importance of the high glycogen content and the high phosphorylase activity in the heart conduction system was discussed.