Subcellular distribution of energy metabolites in the pre‐ischaemic and post‐ischaemic perfused working rat heart

Isolated working rat hearts were subjected to 20 min of global ischaemia and either 5 min or 15 min of reperfusion. The subcellular distribution of ATP, ADP, AMP, phosphocreatine and Pi were determined before and after ischaemia by the method of non‐aqueous tissue fractionation. Ventricular function and the cytosolic, mitochondrial and ATPase‐associated compartmentation of metabolites were measured. After 5 min of reperfusion, only 13±9% of the pre‐ischaemic contractile function was restored compared to 67±8% after 15 min reperfusion. ATP was reduced in all cellular compartments after 5 min of reperfusion but was only decreased from pre‐ischaemic values in the cytosolic compartment after 15 min of reperfusion (17.1±3.9 nmol/mg vs. 4.3±1.5 nmol/mg total protein; P