Oscillatory signaling and insulin release in human pancreatic beta-cells exposed to strontium

Endocrinology. 1997 Aug;138(8):3161-5. doi: 10.1210/endo.138.8.5296.

Abstract

Oscillatory signaling and insulin release were studied in isolated pancreatic islets and beta-cells obtained from human cadaveric organ donors. Taking advantage of Sr2+ as an analog for Ca2+, it was possible to demonstrate glucose-induced rhythmic activity in individual beta-cells identified by immunostaining. Glucose-induced slow oscillations of Sr2+ (frequency, 0.1-1.0/min) were sometimes seen at a sugar concentration as low as 3 mM. Addition of 20 nM glucagon resulted in a broadening of the oscillations or in their transformation into sustained elevation. Moreover, the presence of glucagon resulted in the appearance of short transients of Sr2+, which disappeared after exposure to the intracellular Ca2+-adenosine triphosphatase inhibitor thapsigargin. Digital image analyses indicated that slow oscillations can be synchronized among cells in small aggregates and intact islets. The rhythmic activity in the glucose-stimulated beta-cell had its counterpart in pulsatile insulin release when single islets were perifused with a Sr2+-containing medium. It is concluded that the human beta-cell has oscillatory signaling for insulin release similar to that observed in experimental animals.

MeSH terms

  • Adult
  • Calcium / pharmacology
  • Calcium-Transporting ATPases / antagonists & inhibitors
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Glucagon / pharmacology
  • Glucose / pharmacology
  • Humans
  • Hypoglycemic Agents / pharmacology
  • Immunohistochemistry
  • Insulin / metabolism*
  • Islets of Langerhans / cytology*
  • Islets of Langerhans / metabolism*
  • Middle Aged
  • Signal Transduction / physiology*
  • Strontium / pharmacology*
  • Thapsigargin / pharmacology
  • Time Factors
  • Tolbutamide / pharmacology

Substances

  • Enzyme Inhibitors
  • Hypoglycemic Agents
  • Insulin
  • Thapsigargin
  • Glucagon
  • Tolbutamide
  • Calcium-Transporting ATPases
  • Glucose
  • Calcium
  • Strontium