Effects of ischemia on metabolite concentrations in dog renal cortex

To investigate the effects of ischemia on renal metabolites, sequential slices of renal cortex were removed during 5 min of renal artery occlusion and for 5 min after release of occlusion. ATP concentrations rapidly fell during ischemia and rose during the postischemic period. Based on the rate of decline of ATP concentrations, the rate of ATP production was estimated to be 0.5 mumol ATP/g/min. This is considerably less than the rate of ATP production estimated from renal O2 consumption. During ischemia, AMP concentrations rose, confirming the activity of adenylate kinase. The control lactate/pyruvate ratio suggested that dog kidney cytosol is more reduced than the cytosol of rat liver and kidney. During ischemia, the lactate concentrations and the lactate/pyruvate ratio of dog renal cortex increased as expected, and fell after restoration of blood flow. beta-Hydroxybutyrate concentrations are considerably lower than those previously reported for rat liver and kidney. The beta-hydroxybutyrate/acetoacetate ratio was not measurable during ischemia. However, the mitochondrial redox state, calculated from the glutamate/alpha-ketoglutarate . NH+4 ratio, was similar to previous reports and this ratio appropriately changed during the ischemic and post-ischemic period.