Significance of enzyme release from ischemic isolated rat heart.

Whole-heart ischemia has been induced in isolated working rat heart. The distribution of the reduced coronary flow was even, as judged by 3H-antipyrine autoradiographs. Reducing the coronary flow resulted in myocardial ischemia, as indicated by a lowered tissue content of glycogen, ATP and creatine phosphate and accumulation of lactate. After a reperfusion period of 30 min there was a restoration of glycogen, ATP and creatine phosphate for hearts that were ischemic for 5 and 10 min, with a concomitant normalization of tissue lactate. Hearts that were ischemic for 30 min did not show restoration of high energy phosphates and glycogen. There was a leakage of ASAT, CK and LD in all groups of hearts, suggesting that a release of these enzymes does not necessarily indicate an irreversibly damaged myocardial cell.