In order to establish the characteristics of net renal transport and utilization of α-ketoglutarate (α-KG) in the rat, we have precisely quantified the renal blood flow, the urinary flow and the rates of α-KG delivery, filtration, reabsorption or secretion, excretion, uptake or production by an in vivo rat kidney preparation. In normal rats, α-KG uptake was higher than α-KG reabsorption at both endogenous and elevated plasma α-KG concentrations; thus, a net peritubular transport, which was the main supplier of α-KG to the renal cells, took place. Saturation of reabsorption and peritubular transport of α-KG occurred at blood α-KG concentrations about 30 and 150 times above normal, respectively. Acute metabolic acidosis was found to have no effect on renal handling of α-KG. At endogenous plasma α-KG concentrations, alkalosis converted net renal uptake into net renal production of α-KG resulting in addition of α-KG by the renal cells both to blood and to the luminal fluid. Elevation of blood α-KG concentration restored the renal uptake of α-KG. This uptake, which was entirely accounted for by the peritubular transport of α-KG, reached a maximum which was lower than that observed in normal and acidotic rats.
Rat Kidney Uptake Transport α-Ketoglutarate Luminal Basolateral Production
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LeHir M, Dubach UC (1982) Activities of enzymes of the tricarboxylic acid cycle in segments of the rat nephron. Pflügers Arch 395:239–243CrossRefGoogle Scholar
Narins RG, Passonneau JV (1974) 2-Oxoglutarate. Fluorimetric determination. In: Bergmeyer HU (ed) Methods of enzymatic analysis. Academic Press, New York, pp 1580–1584Google Scholar
Phillips RA, Dole VP, Hamilton PB, Emerson K, Archibald RM, Van Slyke DD (1945) Effects of acute hemorrhagie and traumatic shock on renal function in dogs. Am J Physiol 145:314–336Google Scholar
Selleck BH, Cohen JJ (1965) Specific localization of α-ketoglutarate uptake to dog kidney and liver in vivo. Am J Physiol 208:24–37PubMedGoogle Scholar
Sheridan E, Rumrich G, Ullrich KJ (1983) Reabsorption of dicarboxylic acids from the proximal convolution of the rat kidney. Pflügers Arch 399:18–28CrossRefPubMedGoogle Scholar
Silbernagl S (1980) Tubular reabsorption ofl-glutamine studied by free-flow micropuncture and microperfusion of rat kidney. Int J Biochem 12:9–16CrossRefPubMedGoogle Scholar
Ullrich KJ, Fachold H, Rumrich G, Klöss S (1984) Secretion and contrainminal uptake of dicarboxylic acids in the proximal convolution of the rat kidney. Pflügers Arch 400:241–249CrossRefPubMedGoogle Scholar
Ullrich KJ, Rumrich G, Fritzsch G, Klöss S (1987) Contraluminal para-aminohippurate (PAH) transport in the proximal tubule of the rat kidney. Pflügers Arch 408:38–45CrossRefPubMedGoogle Scholar
Vishwarkarma P (1963) The proximal renal tubular transport of α-ketoglutaric acid. Can J Biochem Physiol 41:1099–1104CrossRefGoogle Scholar
Vurek GG, Pegram SE (1966) Fluorimetric method for the determination of nanogram quantities of inulin. Anal Biochem 16:409–419CrossRefGoogle Scholar
Welbourne TC, Balagura-Baruchs S (1972) Renal metabolism of glutamine in dogs during infusion of α-ketoglutaric acid. Am J Physiol 22:663–666Google Scholar
Wolf AV (1941) Total renal blood flow at any urine flow or extraction fraction. Am J Physiol 133:496–497Google Scholar
1.Centre National de la Recherche Scientifique (UA 1177); Laboratoire de Physiologie Rénale et Métabolique, Faculté de Médecine Alexis CarrelInstitut National de la Santé et de la Recherche Médicale (U 80)Lyon Cedex 08France