抄録
In the metabolism of cardiac muscle, carbohydrate metabolism is playing an important part and as an energy source of cardiac contraction in the normal condition, saccarides comes into the first consideration.Since Buedingen introduced the concept of "hypoglykaemische Kardiodystrophie" glucose has been used customary for the treatment of cardiac disorders, but its therapeutical effect has not been established yet. Some people recommend the use of fructose as it is more advantageous than glucose due to its special behavior in the intermediate metabolism, but many people do not agree with this idea as the perfusion experiments with isolated heart were showing negative results.The author admininistered glucose and fructose intravenously into the dog and studied their influences on the oxygen consumption and utilization of pyruvic acid lactic acid and glucose using the method of coronary sinus catheterization. At the same time, using Rotameter the influence of these manoeuvre on the coronary flow was studied.Results were as follows : 1) By the administration of glucose, coronary flow increased, glucose concentration of the coronary blood increased markedly but its utilization was not increased markedly. coronary arteriovenous difference of oxygen decreased and oxygen consumption showed the tendency to decrease. The metabolism seemed to decline anaerobically.2) By the administration of fructose, coronary flow increased and blood concentration of pyruvic acid and lactic acid increased markedly. The increased pyruvic acid is utilized cempletely by the myocardium but the utilization of lactic acid depended upon the concentration of pyruvic acid.3) Fructose itself was not utilized by the myocardium at all, and the change of pyruvic acid and lactic acid which are intermediate metabolite of fructose were observed as an alteration in the body.4) When fructose was administered, oxygen consumption did not increase markedly although the utilization of pyruvic acid by the myocardium increased remarkably.These results suggest that the utilization of pyruvic acid by the cardiac muscle is performed not only through Krebs cycle but also through some other process, such as the formation of acetoin.
