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.