Adenylate degradation products release from the human myocardium during open heart surgery

Purine degradation products were determined in the human heart coronary sinus effluent collected from patients undergoing cardiac surgery, during infusion of a cardioplegic solution. At the onset of cardiopulmonary bypass the mean concentrations of adenosine, inosine and hypoxanthine were 0.1, 0.5 and 0.3 mumol/l, respectively. Ischemic arrest leads to a progressive increase of the respective levels to 1.4 17.8 and 9.6 mumol/l after 60-80 min of ischemia. Xanthine concentration was undetectable (less than 0.2 mumol/l) throughout. A substantial urate release (20 mumol/l) was observed which decreased with the duration of ischemia. Xanthine oxidoreductase activity in human myocardium was found to be below the detection limit (0.1 mU/g wet weight). Thus, urate release represented wash out of urate which had accumulated in the tissue.