Significance of Carbonic Anhydrase for HCO3 Absorption and H+ Secretion in Renal Tubules

  • E. Frömter
Conference paper
Part of the Proceedings in Life Sciences book series (LIFE SCIENCES)

Abstract

In the present paper I shall discuss some problems dealing with the role of carbonic anhydrase in renal bicarbonate absorption I shall consider only the first part of the nephron, the so-called proximal tubule, because this is the site where most of the renal HCO 3 absorption occurs. As observed in micropuncture experiments the proximal tubule absorbs 70%–80% of the filtered Na+ ions and water, ~ 75% of the filtered Clions and ~ 95% of the filtered HCO 3 , as well as practically all of the filtered glucose and amino acid molecules. Microscopically the wall of the proximal tubule consists of a typical single-layered epithelium of uniform, flat cells which are held together at their luminal end by quite leaky terminal bars. All substances which are reabsorbed by the cells enter the cells via the luminal cell membrane (brushborder) and leave the cells via the highly folded peritubular cell membrane. A great number of the transport mechanisms which are located in these cell membranes have been identified in recent years. Briefly we can say that the primum moyens of almost all fluxes is a Na+/K+ pump located in the peritubular cell membrane which consumes energy by splitting ATP. This pump effects many different things. Firstly it brings about active transtubular Na+ ion transport by exporting the Na+ ions, which leak from the lumen into the cell, across the peritubular cell membrane into the interstitial space. Secondly it provides the energy for the absorption of glucose and amino acids — these substances are driven from lumen to cell by cotransport with Na+ ions, accumulate in the cytoplasm and diffuse then into the interstitium along their concentration gradient — and thirdly it builds up the passive driving forces for the absorption of Cl ions and water. Other transport mechanisms, however, are less well defined.

Keywords

Permeability Dioxide Amide Dehydration Bicarbonate 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Berliner RW (1952) Renal secretion of potassium and hydrogen ions. Fed Proc 11: 695–700Google Scholar
  2. 2.
    Cabantchik ZE, Rothstein A (1972) The nature of the membrane sites controlling anion permeability of human red blood cells as determined by studies with disulfonic stilbene derivatives. J Membr Biol 10: 311–330CrossRefGoogle Scholar
  3. 3.
    Cohen LH, Mueller A, Steinmetz PR (1978) Inhibition of the bicarbonate exit step in urinary acidification by a disulfonic stilbene. J Clin Invest 61: 981–986CrossRefGoogle Scholar
  4. 4.
    Edelman A, Teulon J, Anagnostopoulos T (1978) The effect of a disulfonic acid stilbene on proximal cell membrane potential in Necturus kidney. Biochim Biophys Acta 514: 137–144CrossRefGoogle Scholar
  5. 5.
    Frömter E (1977) Magnitude and significance of the paracellular shunt path in rat kidney proximal tubule. In: Kramer M, Lauterbach F (eds) Intestinal permeation. Excerpta Medica, Amsterdam, pp 166–178Google Scholar
  6. 6.
    Frömter E (1978) Primary and secondary active transport mechanisms in rat renal proximal tubule. In: Ullrich KJ, Vogel HG (eds) New aspects on renal function. Excerpta Medica, Amsterdam, pp 27–36Google Scholar
  7. 7.
    Frömter E, Sato K (1976) Electrical events in active H+/HCO3 transport across rat kidney proximal tubular epithelium. In: Kasbekar DK, Sachs G, Rehm WS (eds) Gastric hydrogen ion secretion. Dekker, New York, pp 382–403Google Scholar
  8. 8.
    Frömter E, Sato K, Gessner K (1976) Electrical studies on the mechanism of H+/HCO3 transport across rat kidney proximal tubule. In: Giovannetti S, Bonomini V, D’Amico G (eds) 6th Int Congr Nephrol. Karger, Basel, pp 108–112Google Scholar
  9. 9.
    Karlmark B, Danielson BG (1974) Titratable acid, PCO2, bicarbonate and ammonium ions along the rat proximal tubule. Acta Physiol Scand 91: 243–258CrossRefGoogle Scholar
  10. 10.
    Lang F, Quehenberger P, Greger R, Oberleithner H (1978) Effect of benzolamide on luminal pH in proximal convoluted tubules of the rat kidney. Pflügers Arch 375: 39–43CrossRefGoogle Scholar
  11. 11.
    Leder O (1969) Die intrazelluläre Verteilung der Carboanhydrase in der Niere von Ratten und Mäusen. Pflügers Arch 297: R54ADSGoogle Scholar
  12. 12.
    Maren TH (1969) Renal carbonic anhydrase and the pharmacology of sulfonamide inhibitors. In: Hercken H (ed) Handb Exp Pharmacol, vol 24. Springer, Berlin Heidelberg New York, pp 195–256Google Scholar
  13. 13.
    Meng K (1972) Die am Nierentubulus wirksamen Diureticakonzentrationen. In: Hohenegger M (ed) Biochemische Aspekte der Nierenfunktion. Goldmann, München, pp 301–310Google Scholar
  14. 14.
    Pitts RF, Alexander RS (1945) The nature of the renal tubular mechanism for acidifying the urine. Am J Physiol 144: 239–254Google Scholar
  15. 15.
    Radtke HW, Rumrich G, Kinne-Saffran E, Ullrich KJ (1972) Dual action of acetazolamide and furosemide on proximal volume absorption in the rat kidney. Kidney Int 1: 100–105CrossRefGoogle Scholar
  16. 16.
    Rector FC, Carter NW, Seldin DW (1965) The mechanism of bicarbonate reabsorption in the proximal and distal tubules of the kidney. J Clin Invest 44: 278–290CrossRefGoogle Scholar
  17. 17.
    Sohtell M (1979) CO2 along the proximal tubules in the rat kidney. Acta Physiol Scand 105: 146–155CrossRefGoogle Scholar
  18. 18.
    Steels PS, Boulpaep EL (1976) Effect of pH on ionic conductances of the proximal tubule epithelium and the role of buffer permeability. Fed Proc 35: R465Google Scholar
  19. 19.
    Ullrich KJ, Capasso G, Rumrich G, Papavassiliou F, Klöss S (1977) Coupling between proximal tubular transport processes. Studies with ouabain, SITS and HCO3-free solutions. Pflügers Arch 368: 245–252CrossRefGoogle Scholar
  20. 20.
    Vieira FL, Malnic G (1968) Hydrogen ion secretion by rat renal cortical tubules as studied by an antimony microelectrode. Am J Physiol 214: 710–718Google Scholar
  21. 21.
    Walser M, Mudge GH (1960) Renal excretory mechanisms. In: Comar CL, Bronner F (eds) Mineral metabolism. Academic Press, London New York, pp 287–336Google Scholar
  22. 22.
    Wistrand PJ, Kinne R (1977) Carbonic anhydrase activity of isolated brush border and basal-lateral membranes of renal tubular cells. Pflügers Arch 370: 121–126CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1980

Authors and Affiliations

  • E. Frömter
    • 1
  1. 1.Max-Planck-Institut für BiophysikFrankfurt (Main) 70Germany

Personalised recommendations