Cyclic AMP raises cytosolic Ca2+ and promotes Ca2+ influx in a clonal pancreatic beta-cell line (HIT T-15)

FEBS Lett. 1987 Aug 10;220(1):103-7. doi: 10.1016/0014-5793(87)80884-0.

Abstract

The effect on cytosolic Ca2+ concentration ([Ca2+]i) of cAMP analogues and the adenylate cyclase-stimulating agents forskolin, isoproterenol and glucagon has been examined in an insulin-secreting beta-cell line (HIT T-15) using fura 2. All these manipulations of the cAMP messenger system promoted a rise in [Ca2+]i which was blocked by the Ca2+ channel antagonists verapamil and nifedipine or by removal of extracellular Ca2+. The action of the adenylate cyclase activator forskolin was glucose-dependent. The results suggest that cAMP elevates [Ca2+]i in HIT cells by promoting Ca2+ entry through voltage-sensitive Ca2+ channels, not through mobilization of stored Ca2+. Activation of Ca2+ influx may be an important component of the mechanisms by which cAMP potentiates fuel-induced insulin release.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Benzofurans / metabolism
  • Calcium / metabolism*
  • Cell Line
  • Colforsin / pharmacology
  • Cricetinae
  • Cyclic AMP / pharmacology*
  • Cytosol / metabolism*
  • Egtazic Acid / pharmacology
  • Fura-2
  • Insulin / metabolism
  • Ion Channels / drug effects
  • Islets of Langerhans / metabolism*
  • Verapamil / pharmacology

Substances

  • Benzofurans
  • Insulin
  • Ion Channels
  • Colforsin
  • Egtazic Acid
  • Verapamil
  • Cyclic AMP
  • Calcium
  • Fura-2