Time and amplitude regulation of pulsatile insulin secretion by triggering and amplifying pathways in mouse islets

FEBS Lett. 2002 Oct 23;530(1-3):215-9. doi: 10.1016/s0014-5793(02)03491-9.

Abstract

Glucose-induced insulin secretion is pulsatile. We investigated how the triggering pathway (rise in beta-cell [Ca(2+)](i)) and amplifying pathway (greater Ca(2+) efficacy on exocytosis) influence this pulsatility. Repetitive [Ca(2+)](i) pulses were imposed by high K(+)+ diazoxide in single mouse islets. Insulin secretion (measured simultaneously) tightly followed [Ca(2+)](i) changes. Lengthening [Ca(2+)](i) pulses increased the duration but not the amplitude of insulin pulses. Increasing glucose (5-20 mmol/l) augmented the amplitude of insulin pulses without changing that of [Ca(2+)](i) pulses. Larger [Ca(2+)](i) pulses augmented the amplitude of insulin pulses at high, but not low glucose. In conclusion, the amplification pathway ensures amplitude modulation of insulin pulses whose time modulation is achieved by the triggering pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism
  • Female
  • Glucose / administration & dosage
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / metabolism*
  • Kinetics
  • Mice

Substances

  • Insulin
  • Glucose
  • Calcium