Distribution of glycolysis and gluconeogenesis in perfused chicken kidney

Regional metabolism of glucose in chicken kidneys was studied in kidneys perfused with either an arterial system or a portal system. Provided that kidneys were perfused with oxygenated buffer solution at a flow rate of 5 ml/min per gram of kidney in both perfusion systems, oxygenation of the kidney was achieved, as judged by the rates of O2 uptake and the formation of lactate, gluconeogenesis, and the ratio of lactate to pyruvate. The rate of formation of lactate and pyruvate during glucose metabolism, in the presence or absence of KCN, was markedly higher with the arterial system than with the portal system. The rate of gluconeogenesis was equal with both perfusion systems but the rate was modulated by the type of substrate used. With succinate as substrate, ouabain inhibited glucose production and O2 uptake in both perfusion systems. With lactate and pyruvate as substrate, ouabain had no effect on glucose production in both perfusion systems, whereas the inhibition of O2 uptake by ouabain was greater with the arterial system than with the portal system. From the viewpoint of the accepted morphological components of the blood supply, these results suggest that chicken renal gluconeogenesis occurs in the cortex and that glycolysis occurs in medullary structures.