Glucose Utilization by the Working Rat Heart 1

Abstract

Summary

Rat hearts were perfused in an apparatus in which coronary flow, cardiac output, left ventricular pressure, rate of rise of left ventricular pressure (dp/dt) and external cardiac work could be measured. The effects of the presence and absence of exogenous glucose were compared. In the presence of glucose stable performance lasted longer than without substrate. When the heart failed cardiac output, left ventricular pressure, maximal dp/dt and cardiac work declined simultaneously. At the time of failure endogenous cardiac glycogen stores had declined to the same level whether or not exogenous glucose had been furnished. The hexose cost of cardiac work was greater when glucose was furnished, suggesting whatever hexose was available was more completely metabolized in the absence of exogenous substrate.