Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Dynamics of the cationic, bioelectrical and secretory responses to formycin A in pancreatic islet cells

In English

Författare

  • Philippe Lebrun
  • Erik Renström
  • Marie-Hélène Antoine
  • Krister Bokvist
  • Mats Holmquist
  • Patrik Rorsman
  • W J Malaisse

Summary, in English

The dynamics of the cationic, bioelectrical and secretory responses to formycin A were monitored in pancreatic islet cells in order to assess whether this adenosine analogue, which is known to be converted to formycin A 5'-triphosphate in isolated islets, triggers the same sequence of ionic events as that otherwise involved in the process of nutrient-stimulated insulin release and currently attributed to an increase in adenosine 5'-triphosphate (ATP) generation rate. Unexpectedly, formycin A first increased 86Rb outflow, decreased 45Ca outflow and inhibited insulin release from prelabelled islets perifused at physiological or higher concentrations of D-glucose. This early inhibitory effect of formycin A upon insulin release coincided, in perforated patch whole-cell recordings, with an initial transient increase of ATP-sensitive K+ channel activity. A positive secretory response to formycin A, still not associated with any decrease in K+ conductance, was only observed either immediately after formycin A administration to islets already exposed to glibenclamide or during prolonged exposure to the adenosine analogue. This coincided with an increase of cytosolic Ca2+ concentration in intact B-cells and a greater increase of membrane capacitance in response to depolarization in B-cells examined in the perforated patch whole-cell configuration. The latter stimulation of exocytotic activity could not be attributed, however, to any increase in peak or integrated Ca2+ current. Thus, the mode of action of formycin A, or its 5'-triphosphate ester, in islet cells obviously differs from that currently ascribed to endogenous ATP in the process of nutrient-stimulated insulin release.

Publiceringsår

1996

Språk

Engelska

Sidor

353-362

Publikation/Tidskrift/Serie

Pflügers Archiv

Volym

431

Issue

3

Dokumenttyp

Artikel i tidskrift

Förlag

Springer

Ämne

  • Endocrinology and Diabetes

Nyckelord

  • Insulin release
  • Pancreatic islet
  • Formycin A

Status

Published

Forskningsgrupp

  • Diabetes - Islet Patophysiology

ISBN/ISSN/Övrigt

  • ISSN: 0031-6768