Advertisement

Pflügers Archiv

, Volume 329, Issue 4, pp 283–306 | Cite as

Influence of bicarbonate-CO2- and glycodiazine buffer on the secretion of the isolated cat's pancreas

  • I. Schulz
  • F. Ströver
  • B. Kasprik
Article

Summary

The isolated cat pancreas was perfused with solutions containing different concentrations of bicarbonate- or glycodiazine buffer. The concentrations of the different buffer components were varied in order to determine the rate-limiting component.
  1. 1.

    The rates of bicarbonate and fluid secretion were proportional to the respective concentrations of the bicarbonate anion and total bicarbonate in the perfusate.

     
  2. 2.

    In only 2 of 9 experiments could the secretory rate of fluid and bicarbonate be varied by altering the CO2-pressure of the perfusate.

     
  3. 3.

    Glycodiazine (Redul®) can partially replace the bicarbonate CO2 buffer in its ability to promote water and solute secretion.

     
  4. 4.

    The rate-limiting step for the enhancement of the glycodiazine and concomitant fluid secretion is the anion concentration in the perfusate, whereas by increasing concentrations of the undissociated acid of this buffer the secretory flow rate and total buffer secretion can be decreased.

     

Considering also earlier findings with sulfamerazine buffer a model is proposed where a H+/OH ion separation takes place at the luminal cell border of the exocrine pancreas cells. Undissociated acid as well as buffer anions neutralize the H+ resp. the OH ions thereby promoting the buffer secretion.

The rate-limitation with each buffer component seems to be dependent on its concentration and permeation properties. The inhibition of pancreatic secretion by the undissociated glycodiazine is presumably caused by its effects on the mitochondrial energy production.

Key-Words

Pancreatic Secretion Bicarbonate Secretion H+ Ion Transport Buffer Secretion 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Bell, R. P.: The proton in chemistry. Ithaca, N. Y.: Cornell University Press 1959.Google Scholar
  2. 2.
    Case, R. M., Harper, A. A., Scratcherd, T.: Water and electrolyte secretion by the perfused pancreas of the cat. J. Physiol. (Lond.)196, 133–149 (1968).Google Scholar
  3. 3.
    —, Scratcherd, T., Wynne, R. D'A.: The origin and secretion of pancreatic juice bicarbonate. J. Physiol. (Lond.)210, 1–15 (1970).Google Scholar
  4. 4.
    Kramer, M., Hecht, G., Langecker, H., Harwart, A., Richter, K.-D., Gloxhuber, Ch.: Pharmakologie des 2-Benzolsulfonamido-5 (p-methoxy-äthoxy)-pyrimidins (Glykodiazin), einer neuen blutzuckersenkenden Verbindung. Arzneimittel-Forsch. (Drug Res.)14, 377–385 (1964).Google Scholar
  5. 5.
    Maren, T. H.: Carbonic anhydrase: chemistry, physiology, and inhibition. Physiol. Rev.47, 595–781 (1967).Google Scholar
  6. 6.
    Pak, B. H., Hong, S. S., Pak, H. K., Hong, S. K.: Effects of acetazolamide and acid-base changes on biliary and pancreatic secretion. Amer. J. Physiol.210, 624–628 (1966).Google Scholar
  7. 7.
    Ramsay, J. A., Brown, R. H. J., Croghan, P. C.: Electrometric titration of chloride in small volumes. J. exp. Biol.32, 822–829 (1955).Google Scholar
  8. 8.
    Rawls, J. A., Jr., Wistrand, P. J., Maren, T. H.: Effects of acid base changes and carbonic anhydrase inhibition on pancreatic secretion. Amer. J. Physiol.205, 651–657 (1963).Google Scholar
  9. 9.
    Rector, F. G., Jr., Carter, N. W., Seldin, D. W.: The mechanism of bicarbonate reabsorption in the proximal and distal tubules of the kidney. J. clin. Invest.44, 278–290 (1965).Google Scholar
  10. 10.
    Sachs, G., Blum, A. L., Hirschowitz, B. I.: Mechanisms of H+ secretion. Proc. of the Intern. Union of Physiol. Sciences, Vol. VIII, p. 95. XXV. Intern. Congress, Munich 1971.Google Scholar
  11. 11.
    Schulz, I., Ströver, F., Ullrich, K. J.: Lipid soluble weak organic acid buffers as “Substrate” for pancreatic secretion. Pflügers Arch.323, 121–140 (1971).Google Scholar
  12. 12.
    —, Yamagata, A., Weske, M.: Micropuncture studies on the pancreas of the rabbit. Pflügers Arch.308, 277–290 (1969).Google Scholar
  13. 13.
    Ullrich, K. J., Rumrich, G., Radtke, H. W., Klöss, S.: Effect of bicarbonate and other lipid soluble buffers on the isotonic fluid absorption in the proximal tubule of the rat kidney. Pflügers Arch.319, R 72 (1970).Google Scholar

Copyright information

© Springer-Verlag 1971

Authors and Affiliations

  • I. Schulz
    • 1
  • F. Ströver
    • 1
  • B. Kasprik
    • 1
  1. 1.Max-Planck-Institut für BiophysikFrankfurt a. MainGermany

Personalised recommendations