Improved sodium and PAH transport in the isolated fluorocarbon-perfused rat kidney

The effect of an artificial O2 carrier (emulsion of the perfluorochemical FC43 with Pluronic-F-108) on the functional capability of the isolated perfused rat kidney was tested. In control series hydroxyethyl starch (HES) instead of fluorocarbon was used. Improving O2 supply in FC 43 experiments raised Na reabsorption to 149 mumol/g x min compared to 84.1 mumol/g x min in HES experiments. In the presence of PAH, however, Na reabsorption in FC 43 experiments was only 115 mumol/g x min. In both series, perfusion flow, calculated on the basis of CPAH, remained below the directly measured flow rate, unless analysis included all metabolites of PAH. N-acetylated metabolites of PAH were released at a 5 times higher rate by kidneys perfused with FC 43 than by HES-perfused organs. These results demonstrate that sufficient O2 supply is critical both for reabsorption of Na+ and for handling of PAH. Increased tubular Na reabsorption in the absence of PAH indicates that even during perfusion with FC 43 O2 supply is marginal.