Intraislet Ghrelin Signaling Does Not Regulate Insulin Secretion From Adult Mice.

Published

Journal Article

Exogenous ghrelin reduces glucose-stimulated insulin secretion and endogenous ghrelin protects against hypoglycemia during starvation. Islet ε-cells produce ghrelin and δ-cells express growth hormone secretagogue receptor (GHSR), suggesting the possibility of a paracrine mechanism for islet ghrelin to reach high local concentrations and affect insulin secretion. GHSR has high constitutive activity and may act independently of ghrelin. The objective in this study was to determine whether an intraislet ghrelin-GHSR axis modulates insulin secretion and glucose metabolism using mouse models lacking ghrelin (Ghrl-/- ) or GHSR (Ghsr-/- ). Ghsr-/- and Ghsr+/+ mice had comparable islet ghrelin concentrations. Exogenous ghrelin decreased insulin secretion in perifused isolated islets in a GHSR-dependent manner. Islets isolated from Ghrl-/- or Ghsr-/- mice did not differ from controls in glucose-, alanine-, or GLP-1-stimulated insulin secretion during perifusion. Consistent with this finding, Ghrl-/- and Ghsr-/- male mice studied after either 6 or 16 h of fasting had blood glucose concentrations comparable with those of controls following intraperitoneal glucose, or insulin tolerance tests, or after mixed nutrient meals. Collectively, our data provide strong evidence against a paracrine ghrelin-GHSR axis mediating insulin secretion or glucose tolerance in lean, chow-fed adult mice.

Full Text

Cited Authors

  • Gray, SM; Niu, J; Zhang, A; Svendsen, B; Campbell, JE; D'Alessio, DA; Tong, J

Published Date

  • September 2019

Published In

Volume / Issue

  • 68 / 9

Start / End Page

  • 1795 - 1805

PubMed ID

  • 31201280

Pubmed Central ID

  • 31201280

Electronic International Standard Serial Number (EISSN)

  • 1939-327X

Digital Object Identifier (DOI)

  • 10.2337/db19-0079

Language

  • eng

Conference Location

  • United States