Comparison of the effect of glucose and fructose on the recovery of the heart preparation.

Reactions of the cardiac muscle of the rat in vitro were investigated in the present study. Cardiac muscle was perfused by Langendorf's method; perfusion pressure was 80 cm H2O and the temperature of the perfusion solution 37 degrees C. The perfusion solution was aerated with a gas mixture of oxygen (95%) and carbon dioxide (5%). Potassium citrate solution was used for heart arrest, and heart function was recovered by infusion of Locke's solution, plus glucose, fructose or sucrose. During recovery the amplitude and frequenty of heart beats, the lactic acid in the drained perfusion solution, pH and potassium concentration were measured. The use of glucose, fructose or sucrose made no significant difference to any of these parameters. Next, the metabolism of glucose and fructose in the heart was investigated by means of D(U-14C)-glucose nad D(U-14C)-fructose. Radioactive lactic acid was detected in the drained perfusion solution with D(U-14C)-glucose, but not when D(U-14C)-fructose was used. The radioactivity incorporated into glycogen by the heart was also larger with D(U-14C)-glucose than with D(U-14C)-fructose. On a metabolic basis the use of glucose for resuscitation would seem to be more appropriate than fructose.