Intermediary metabolism has been studied in a viable suspension of renal proximal tubules isolated from dogs before and after 48 h of a 60 min period of renal ischemia by clamping the renal artery. The study consisted in measurements of tubular uptake/production of glucose, lactate, glutamine, glutamate,α-ketoglutarate, alanine, ammonium, and oxygen, using as substrates either glutamine 1 or 5 mM (+ glutamate 0.1 or 0.5 mM) or lactate 1 or 5 mM (+ pyruvate 0.1 or 0.5 mM). The combination of glutamine + lactate was also studied. Data revealed that the gluconeogenic ability of the postischemic tubules was maintained, with the exception of glutamine 5 mM as substrate (8.5±2.1 vs 15.4±2.1 n`mol/min/g in control tubules). The production of NH4was also decreased only with this substrate (from 214±15 to 165±9 n`mol/min/g). Lactate extraction was decreased in the postischemic tubules, but the difference was only significant when lactate + glutamine 1 mM was used as substrate (72±12 vs 44±6 n`mol/g/min). Postischemic tubules showed a greater oxygen consumption when either glutamine or lactate 1 mM were used, but lower ouabain-inhibitable O2consumption when these substrates were used at 5 mM. These data revealed a modification of the metabolic profile of proximal tubules during the recovery of transient renal ischemia.