Somatostatin and insulin mediate glucose-inhibited glucagon secretion in the pancreatic α-cell by lowering cAMP

Amicia D. Elliott, Alessandro Ustione, David W. Piston

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

Somatostatin and insulin mediate glucose-inhibited glucagon secretion in the pancreatic a-cell by lowering cAMP. Am J Physiol Endocrinol Metab 308: E130-E143, 2015. First published November 18, 2014; doi:10.1152/ajpendo.00344.2014.-The dysregulation of glucose-inhibited glucagon secretion from the pancreatic islet a-cell is a critical component of diabetes pathology and metabolic disease. We show a previously uncharacterized [Ca2+]i-independent mechanism of glucagon suppression in human and murine pancreatic islets whereby cAMP and PKA signaling are decreased. This decrease is driven by the combination of somatostatin, which inhibits adenylyl cyclase production of cAMP via the G?i subunit of the SSTR2, and insulin, which acts via its receptor to activate phosphodiesterase 3B and degrade cytosolic cAMP. Our data indicate that both somatostatin and insulin signaling are required to suppress cAMP/PKA and glucagon secretion from both human and murine ?-cells, and the combination of these two signaling mechanisms is sufficient to reduce glucagon secretion from isolated ?-cells as well as islets. Thus, we conclude that somatostatin and insulin together are critical paracrine mediators of glucose-inhibited glucagon secretion and function by lowering cAMP/PKA signaling with increasing glucose.

Original languageEnglish
Pages (from-to)E130-E143
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Volume308
Issue number2
DOIs
StatePublished - Jan 15 2015
Externally publishedYes

Keywords

  • Cyclic AMP
  • Glucagon
  • Insulin
  • Pancreatic islets
  • Somatostatin

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