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High Affinity SH-Groups on the Surface of Pancreas Cells Involved in Secretin Stimulation

  • I. Schulz
  • S. Milutinović
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 84)

Abstract

The effect of p-chloromercuribenzoate (pCMB) on secretin stimulated pancreatic fluid secretion in vivo was investigated and compared with its effect on secretin binding and secretin stimulated adenylate cyclase in isolated pancreatic plasma membranes in vitro. A biphasic effect of pCMB “was observed. At low concentrations (10-9 – 5 × 10-8M) pCMB stimulated adenylate cyclase activity, secretin binding and secretin stimulated pancreatic fluid secretion by ~ 50, 25 and 100%, respectively. At higher concentrations (10-7 – 10-5M) pCMB inhibited secretin binding by 50%. In the same range of pCMB concentrations secretin stimulated adenylate cyclase was inhibited in a dose dependent fashion. Basal adenylate cyclase activity was much less susceptible to the inhibition by pCMB since about 50 times greater concentration of pCMB is required for half-maximal inhibition (5 × 10-5M and 10-6M, respectively).

To restrict the effect of the SH group reagent to the outer mem­brane surface a large Dextrgn-linked derivative of pCMB was used in in vivo experiments. At 10-8M this compound inhibited secretin induced fluid secretion by 47%. About one half of this inhibition is due to the blocking of SH groups involved in glucose transport since it is abolished by replacing glucose in perfusion fluid by substrates of the Krebs-cycle. The other half of inhibition is directly related to the secretin action since it is abolished by replacing secretin by dibutyryl cAMP and theophylline.

The data show that accessible SH groups located at the cell surface are directly involved in secretin binding and adenylate cyclasestimulation. Since the apparent Km for secretin stimulation of adenylate cyclase and the Kd for secretin binding were in agreement and since pCMB stimulated and inhibited both secretin binding and se- cretin stimulated adenylate cyclase activity in the same concentration range it-is suggested that the binding of secretin to its receptor is the rate determining step in the stimulation of adenylate cyclase by this hormone. The biphasic action of pCMB can be best interpreted with the assumption that several categories of SH-groups are present in the plasma membrane.

Keywords

Adenylate Cyclase Adenylate Cyclase Activity Fluid Secretion Dibutyryl cAMP Adenylate Cyclase System 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    BATAILLE, D., FREYCHET, P., ROSSELIN, G.: Endocrinology 95 (1974) 713.PubMedCrossRefGoogle Scholar
  2. 2.
    CASE, R.M., HARPER, A.A., SCRATCHERD, T.: J. Physiol. London 196 (1968) 133.PubMedGoogle Scholar
  3. 3.
    CASE, R.M., SCRATCHERD, T.: J. Physiol. London 223 (1971) 649.Google Scholar
  4. 4.
    CZECH, M.P., LAWRENCE, J.C., LYNN, W.S.: Proc. nat. Acad. Sci., Wash. 71 (1974) 4173.CrossRefGoogle Scholar
  5. 5.
    ELDJARN, L., JELLEUM, E.: Acta Chem. Scand. 17 (1963) 2610.Google Scholar
  6. 6.
    EPSTEIN, D.L.: Exp. Eye Res. 11 (1971) 351.PubMedCrossRefGoogle Scholar
  7. 7.
    HEWITT, J., PILLION, D., LEIBACH, F.H.: Biochim. “biophys. Acta 363 (1974) 267.PubMedCrossRefGoogle Scholar
  8. 8.
    JOCELYN, P.C.: Biochemistry of the SH Group. Academic Press. London, New York (1972).Google Scholar
  9. 9.
    KRISHNA, G., WEISS, B., BRODIE, B.B.: J. Pharmacol, exp. Ther. 163 (1968) 379.Google Scholar
  10. 10.
    KWOCK, L., WALLACH, D.F.H., HEFTER, K.: Biochim. biophys. Acta 419 (1976) 93.PubMedCrossRefGoogle Scholar
  11. 11.
    MILUTINOVIC, S., SCHULZ, I., ROSSELIN, G.: Biochim. biophys. Acta, in press.Google Scholar
  12. 12.
    OHTA, H., MATSUMOTO, J., NAGANO, K., FUJITA, M., NAKAO, M.: Biochem. Biophys. Res. Commun. 42 (1971) 1127.Google Scholar
  13. 13.
    OYE, I., SUTHERLAND, E.W.: Biochim. biophys. Acta 127 (1966) 347.PubMedCrossRefGoogle Scholar
  14. 14.
    RODBELL, M.: Current Topics in Biochemistry. (Anfinsen, C.B., Goldberger, R.F., Schechter, A.N., Eds.). Academic Press. New York (1972) 187.Google Scholar
  15. 15.
    ROTHSTEIN, A.: Current Topics in Membranes and Transport.(Brenner, F., Kleinzeller, A., Eds.). Academic Press. New York. 1 (1970) 143.Google Scholar
  16. 16.
    SCHRAMM, M., NAIM, E.: J. biol. Chem. 245 (1970) 3225.PubMedGoogle Scholar
  17. 17.
    SIMON, B., ZIMMERSCHIED, G., KINNE-SAFFRAN, E.M., KINNE, R.: J. Membr. Biol. 14 (1973) 85.PubMedCrossRefGoogle Scholar
  18. 18.
    SUTHERLAND, E.W., ROBISON, G.A., BUTCHER, R.W.: Circulation 37 (1968) 279.Google Scholar
  19. 19.
    TOMAS I. V., KORETZ, S., RAY, T.K., DUNNICK, J., MARINETTI, G.V.: Biochim. biophys. Acta 211 (1970) 31.CrossRefGoogle Scholar
  20. 20.
    WIZEMAM, V., SCHULZ, I.: Pflügers Arch. 339 (1973) 317.CrossRefGoogle Scholar
  21. 21.
    WIZEMANN, V., SCHULZ, I., SIMON, B.: Biochim. biophys. Acta 307 (1973) 366.PubMedCrossRefGoogle Scholar

Copyright information

© Plenum Press, New York 1977

Authors and Affiliations

  • I. Schulz
    • 1
  • S. Milutinović
    • 1
  1. 1.Max-Planck-Institut für BiophysikFrankfurt/MainGermany

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