Involvement of GTP-binding protein in pancreatic cAMP-mediated exocytosis

Kozo Sato, Atsushi Ohsaga, Takako Oshiro, Sadayoshi Ito, Yoshio Maruyama

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We studied cAMP-mediated exocytosis in rat pancreatic acinar cells. We monitored changes in the membrane capacitance (ΔC), which reflects the granule fusion/retrieval process, with whole-cell patch-clamp capacitance measurement. The rise in cellular cAMP, caused indirectly by receptor activation by vasoactive intestinal polypeptide or directly by dibutyryl cyclic AMP, was able to induce an increase in ΔC independently of cellular Ca2+. Using the latter stimulation, we estimated the magnitude of the response to internal GTPγS [guanosine 5′-(γ-thio)trisphosphate] and/or GDPβS [guanosine 5′-(β-thio)diphosphate]. The internal GTPγS and GDPβS amplified and depressed the response, respectively. Thus, the cellular cAMP alone can trigger granule insertion independently of cellular Ca2+ and it can be controlled by cellular GTP-binding proteins, presumably those belonging to the Rab family.

Original languageEnglish
Pages (from-to)394-398
Number of pages5
JournalPflugers Archiv European Journal of Physiology
Issue number3
Publication statusPublished - 2002


  • Cyclic AMP
  • Exocytosis
  • GTP-binding protein
  • Membrane capacitance
  • Pancreatic acinar cell

ASJC Scopus subject areas

  • Physiology
  • Clinical Biochemistry
  • Physiology (medical)


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