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Contribution of leucine to oxidative metabolism of the rat medullary thick ascending limb

  • Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands
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Abstract

It has recently been reported that branched-chain amino acid aminotransferase (BCAATase) is inhomogeneously distributed in the kidney. BCAATase activity is several-fold higher in the medullary thick ascending limb (MTAL) than in other nephron segments. The present work was designed to determine whether leucine, a branched-chain amino acid (AA), is used as metabolic fuel by this nephron segment. MTAL were isolated from the inner stripe of the outer medulla of adult Sprague Dawley rats by mild enzymatic digestion and appropriate sieving. Leucine aminotransferase activity measured in homogenates of MTAL was 653±52 pmol α-ketoglutarate formed/μg protein per hour, a value threefold higher than that observed in the renal cortex or muscle in the same rats. Substrate oxidation was assessed by measuring14CO2 production from tracer amounts of uniformly labeled14C-amino acids or glucose in isolated MTAL incubated in modified Earle balanced salt solution. When each substrate was offered at a concentration of 1 mM, leucine oxidation was much higher than that of unbranched AA, but fivefold lower than that of glucose. With 1 mM glucose and 1 mM leucine in the medium, leucine oxidation was close to that of glucose (123±8 versus 177±15 pmol CO2/μg protein per hour), probably because glucose contributed to the formation of α-ketoglutarate, a cosubstrate for leucine transamination. Inhibition of salt transport by furosemide (0.1 mM) decreased oxidation of both substrates by 60–70%. Inhibition of salt transport by ouabain (1 mM) decreased glucose oxidation markedly. However, it doubled leucine oxidation when glucose was absent from the medium and decreased leucine oxidation by only 28% when glucose was present. This might be due to an ouabain-dependent alteration in membrane permeability to AA. These findings show that leucine is oxidized in rat MTAL and may contribute to supporting active transport in this segment. This contribution could be important after a protein meal or on high protein diet, situations in which plasma level of branched-chain AA is elevated.

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References

  1. Aftring RP, Block KP, Buse MG (1986) Leucine and isoleucine activate skeletal muscle branched-chain α-keto acid dehydrogenase in vivo. Am J Physiol 250:E599-E604

    Google Scholar 

  2. Aukland K, Johannesen J, Kiil F (1969) In vivo measurements of local metabolic rate in the dog kidney. Effect of mersalyl, chlorothiazide, ethacrynic acid and furosemide. Scand J Clin Lab Invest 23:317–330

    Google Scholar 

  3. Bouby N, Trinh-Trang-Tan MM, Kriz W,Bankir L (1987) Possible role of the thick ascending limb of the urine concentrating mechanism in the protein-induced increase in GFR and kidney mass. Kidney Int 32 (suppl 22):S57-S61

    Google Scholar 

  4. Brezis M, Silva P, Epstein FH (1984) Amino acids induce renal vasodilatation in isolated perfused kidney: coupling to oxidative metabolism. Am J Physiol 247:H999-H1004

    Google Scholar 

  5. Brezis M, Rosen S, Silva P, Epstein FH (1984) Renal ischemia: a new perspective. Kidney Int 26:375–383

    Google Scholar 

  6. Burch HB, Cambon N, Lowry OH (1985) Branched-chain amino acid aminotransferase along the rabbit and rat nephron. Kidney Int 28:114–117

    Google Scholar 

  7. Chamberlin ME, Mandel LJ (1986) Substrate support of medullary thick ascending limb oxygen consumption. Am J Physiol 251:F758-F763

    Google Scholar 

  8. Chang TW, Goldberg AL (1978) Leucine inhibits oxidation of glucose and pyruvate in skeletal muscles during fasting. J Biol Chem 253:3696–3701

    Google Scholar 

  9. Cunarro JA, Weiner MW (1978) Effects of ethacrynic acid and furosemide on respiration of isolated kidney tubules: the role of ion transport and the source of metabolic energy. J Pharmacol Exp Ther 206:198–206

    Google Scholar 

  10. Dawson AG, Hird F Jr, Morton DJ(1967) Oxidation of leucine by rat liver and kidney. Arch Biochem Biophys 122:426–433

    Google Scholar 

  11. Eisenstein AB, Strack I, Gallo-Torres, H, Georgiadis A, Miller ON (1979) Increased glucagon secretion in protein-fed rats: lack of relationship to plasma amino acids. Am J Physiol 236:E20-E27

    Google Scholar 

  12. Epstein FH, Brosnan JT, Tange JD, Ross BD (1982) Improved function with amino acids in the isolated perfused kidney. Am J Physiol 243:F284-F292

    Google Scholar 

  13. Frömter E, Gessner K (1975) Effects of inhibitors and diuretics on electrical potential difference in rat proximal tubule. Pflügers Arch 357:209–224

    Google Scholar 

  14. Geigy Scientific Tables (1981) published by Ciba-Geigy Limited, Basel, Switzerland p 220

  15. Gillim SA, Paxton R, Cook GR, Harris RA (1983) Activity state of the branched chain α-ketoacid dehydrogenase complex in heart, liver, and kidney of normal, fasted, diabetic, and protein starved rats. Biochem Biophys Res Commun 111:74–81

    Google Scholar 

  16. Goldberg DJ, Walesky M, Sherwin RS (1979) Effect of somatostatin on the plasma amino acid response to ingested protein in man. Metabolism 28:866–873

    Google Scholar 

  17. Guder WG, Ross BD (1984) Enzyme distribution along the nephron. Kidney Int 26:101–111

    Google Scholar 

  18. Guder WG, Pürschel S, Wirthensohn G (1983) Renal ketone body metabolism. Distribution of 3-oxoacid CoA-transferase and 3-hydroxybutyrate dehydrogenase along the mouse nephron. Hoppe-Seyler's Z Physiol Chem 364:S1727-S1737

    Google Scholar 

  19. Guder WG, Wagner S, Wirthensohn G (1986) Metabolic fuels along the nephron: pathways and intracellular mechanisms of interaction. Kidney Int 29:41–45

    Google Scholar 

  20. Harbhajan SP, Adibi SA (1978) Leucine oxidation in diabetes and starvation: effects of ketone bodies on branched-chain amino acid oxidation in vitro. Metabolism 27:185–200

    Google Scholar 

  21. Hintz CS, Turk WR, Cambon N, Burch HB, Nemeth PM, Lowry OH (1985) A method for branched-chain amino acid aminotransferase activity in microgram and nanogram tissue samples. Anal Biochem 146:418–422

    Google Scholar 

  22. Hus-Citharel A, Morel F (1986) Coupling of metabolic CO2 production to ion transport in isolated rat thick ascending limbs and collecting tubules. Pflügers Arch 407:421–427

    Google Scholar 

  23. Ichihara A, Koyama E (1966) Transaminase of branched chain amino acids. I. Branched chain amino acids-α-ketoglutarate transaminase. J Biochem 59:160–169

    Google Scholar 

  24. Klein KL, Wang MS, Torikai S, Davidson WD, Kurokawa K (1981) Substrate oxidation by isolated single nephron segments of the rat. Kidney Int 20:29–35

    Google Scholar 

  25. Kurokawa K, Torikai S, Wang M, Klein KL, Kawashima H (1982) Metabolic hererogeneity of the nephron. Miner Electrolyte Metab 7:225–236

    Google Scholar 

  26. Le Bouffant F, Hus-Citharel A, Morel F (1984) Metabolic CO2 production by isolated single pieces of rat distal nephron segments. Pflügers Arch 401:346–353

    Google Scholar 

  27. Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275

    Google Scholar 

  28. Mimura T, Yamada C, Swendseid ME (1968) Influence of dietary protein levels and hydrocortisone administration on the branched-chain amino acid transaminase activity in rat tissues. J Nutr 95:493–498

    Google Scholar 

  29. Mitch WE, Chesney RW (1983) Amino acid metabolism by the kidney. Miner Electrolyte Metab 9:190–202

    Google Scholar 

  30. Odessey R, Goldberg AL (1972) Oxidation of leucine by rat skeletal muscle. Am J Physiol 223:1376–1383

    Google Scholar 

  31. Seney FD Jr, Persson EG, Wright FS (1987) Modification of tubuloglomerular feedback signal by dietary protein. Am J Physiol 252:F83-F90

    Google Scholar 

  32. Trinh-Trang-Tan MM, Bouby N, Coutaud C, Bankir L (1986) Quick isolation of rat medullary thick ascending limbs. Enzymatic and metabolic characterization. Pflügers Arch 407:228–234

    Google Scholar 

  33. Wittner M, Weidtke C, Schlatter E, Di Stefano A, Greger R (1984) Substrate utilization in the isolated perfused cortical thick ascending limb of rabbit nephron. Pflügers Arch 402:52–62

    Google Scholar 

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Authors and Affiliations

  1. INSERM Unité 90, Hôpital Necker, F-75743, Paris Cedex 15, France

    Marie-Marcelle Trinh-Trang-Tan, Olivier Levillain & Lise Bankir

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  1. Marie-Marcelle Trinh-Trang-Tan
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  2. Olivier Levillain
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  3. Lise Bankir
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Trinh-Trang-Tan, MM., Levillain, O. & Bankir, L. Contribution of leucine to oxidative metabolism of the rat medullary thick ascending limb. Pflugers Arch. 411, 676–680 (1988). https://doi.org/10.1007/BF00580865

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  • DOI: https://doi.org/10.1007/BF00580865

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