A polymeric prostaglandin (PGBx) attenuates adenine nucleotide loss during global ischemia and improves myocardial function during reperfusion.

Effects of a synthetic, prostaglandin (PGBx) on energy metabolism in isolated, guinea pig hearts were studied using P-31 nuclear magnetic resonance spectroscopy (NMR) or by direct chemical analysis. Polymeric prostaglandin (500 and 750 ng/ml) attenuated the reduction of ATP and adenine nucleotides during 35 min of total transient ischemia. This occurred despite the absence of any significant preischemic changes in heart rate, contractility or coronary vascular resistance. Preischemic perfusion with PGBx extended the time taken to reach 50% reduction in dP/dt following the first few seconds of ischemia. PGBx had no effect on the development of intracellular acidosis during ischemia. Reperfusion resulted in normalization of phosphocreatine but not ATP concentrations in control and experimental groups. Prostaglandin (750 ng/ml) caused faster and more complete recovery of left ventricular dP/dt following reperfusion. In contrast to untreated hearts, dP/dt in PGBx-treated hearts was significantly higher than preischemic values despite incomplete restoration (70% of control) of ATP levels. These results suggest that the beneficial effects of PGBx observed during myocardial ischemia are unrelated to functionally-induced alterations and that PGBx probably has some direct cellular effect on energy metabolism.