Glucose stimulation of somatostatin-producing islet cells involves oscillatory Ca2+ signaling

Endocrinology. 1996 Feb;137(2):693-7. doi: 10.1210/endo.137.2.8593819.


The cytoplasmic Ca2+ concentration ([Ca2+]i) was measured with fura-2 in individual mouse pancreatic delta-cells identified by immunostaining for somatostatin. A majority of the delta-cells responded to 3 mM glucose with slow oscillations of [Ca2+]i (frequency, 0.1-0.4/min). In originating from a basal level of 60-100 nM and reaching peak values of 200-500 nM, the oscillations resembled those in insulin-secreting beta-cells stimulated by glucose. The rise in glucose to 20 mM resulted in a minor increase in the oscillatory frequency and sometimes in transformation of the oscillations into sustained elevation of [Ca2+]i. The addition of 3 microM L-epinephrine effectively counteracted the increase in [Ca2+]i in response to glucose. The delta-cells reacted with a sustained elevation of [Ca2+]i after raising extracellular K+ to 30.9 mM or adding 1 microM tolbutamide. Analyses using the patch-clamp technique revealed the presence of K+ channels with properties similar to the ATP-sensitive channels in pancreatic beta-cells. It is concluded that regulation of somatostatin release mimics that of insulin, with glucose induction of [Ca2+]i oscillations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / physiology*
  • Cytoplasm / metabolism
  • Epinephrine / pharmacology
  • Female
  • Glucose / pharmacology*
  • Islets of Langerhans / cytology
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / metabolism*
  • Mice
  • Mice, Inbred Strains
  • Oscillometry
  • Osmolar Concentration
  • Patch-Clamp Techniques
  • Potassium Channels / physiology
  • Signal Transduction*
  • Somatostatin / biosynthesis*


  • Potassium Channels
  • Somatostatin
  • Glucose
  • Calcium
  • Epinephrine