Intermediary metabolism in renal proximal tubules in the recovery phase of experimental renal ischemia in dogs.
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, alpha-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 mumol/min/g in control tubules). The production of NH4 was also decreased only with this substrate (from 214 +/- 15 to 165 +/- 9 mumol/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 mumol/g/min). Postischemic tubules showed a greater oxygen consumption when either glutamine or lactate 1 mM were used, but lower ouabain-inhibitable O2 consumption 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.
Fundación Jiménez Díaz-Consejo Superior de Investigaciones Científicas, Madrid, Spain.
I
I
Montañés
A
A
Badía
M A
MA
Rengel
A
A
López-Farré
J M
JM
López-Novoa
D000409:Alanine / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D004285:Dogs; D005947:Glucose / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D005973:Glutamine / Q000378:metabolism; D066298:In Vitro Techniques; D007511:Ischemia / Q000378:metabolism*; D007656:Ketoglutaric Acids / Q000378:metabolism; D007668:Kidney / Q000098:blood supply*; D007687:Kidney Tubules, Proximal / Q000098:blood supply / Q000378:metabolism*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D010101:Oxygen Consumption; D051381:Rats
D005971:Glutamates; D007656:Ketoglutaric Acids; D007773:Lactates; D005973:Glutamine; D019344:Lactic Acid; D018698:Glutamic Acid; D000641:Ammonia; D005947:Glucose; D000409:Alanine