Metabolic oxidation of glucose during early myocardial reperfusion

We have previously studied the relation between long-chain fatty acid and pyruvate metabolism in reperfused myocardium and noted a rapid return of fatty acid oxidation to at least preischemic values accompanied by a marked decrease in pyruvate oxidation. The purpose of the present report is to further characterize carbohydrate metabolism during reflow by describing rates of glucose oxidation using [6-14C]glucose. Oxidative performance was determined with and without preserved fatty acid utilization; the latter condition was effected by oxfenicine, which inhibits palmitoylcarnitine transferase I. In the main protocol, two groups of working swine hearts (n = 18) were perfused aerobically for 30 minutes, rendered regionally ischemic (-60 delta % in anterior descending coronary flow) for 45 minutes, and reperfused at control flows for a final 50 minutes of perfusion. An emulsion of Intralipid with heparin was administered systemically throughout the studies to augment serum fatty acids (average fatty acid values, 1.05 +/- 0.05 mumol/ml for both groups). Serum glucose was monitored and maintained at or about 100 mg/dl with additional infusions of glucose as needed. Oxfenicine (33 mg/kg) was administered systemically by bolus injection at time 0 and 60 minutes of perfusion in nine animals. Decreased mechanical performance, that is, stunning, during reflow was evident in both groups (-50 delta % in regional systolic shortening, p less than or equal to 0.05 compared with aerobic values in the control group, and -32 delta %, p less than or equal to 0.05 compared with aerobic values in treated hearts).(ABSTRACT TRUNCATED AT 250 WORDS)