Ghrelin differentially modulates glucose-induced insulin secretion according to feeding status in sheep

Hideyuki Takahashi, Yohei Kurose, Muneyuki Sakaida, Yoshihiro Suzuki, Shigeki Kobayashi, Toshihisa Sugino, Masayasu Kojima, Kenji Kangawa, Yoshihisa Hasegawa, Yoshiaki Terashima

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Abstract

The present study was conducted to investigate roles of ghrelin in glucose-induced insulin secretion in fasting- and meal-fed state in sheep. Castrated Suffolk rams were fed a maintenance diet of alfalfa hay cubes once a day. Hyperglycemic clamp (HGC) was carried out to examine glucose-induced insulin response from 48 to 53 h (fasting state) and from 3 to 8 h (meal-fed state) after feeding in Experiment 1 and 2 respectively. Total dose of 70 nmol/kg body weight of D-Lys3-GHRP6, a GH secretagogue receptor 1a (GHS-R1a) antagonist, was intravenously administered at 0, 60, and 120 min after the commencement of HGC. In the fasting state, the ghrelin antagonist significantly (P <0.01) enhanced glucose-induced insulin secretion. In the meal-fed state, i.v. administration of synthetic ovine ghrelin (0.04 μg/kg body weight per min during HGC) significantly (P<0.05) enhanced glucose-induced insulin secretion. D-Lys3-GHRP6 treatment suppressed ghrelin-induced enhancement of the insulin secretion. In conclusion, ghrelin has an inhibitory and stimulatory role in glucose-induced insulin secretion via GHS-R1a in fasting- and meal-fed state respectively.

Original languageEnglish
Pages (from-to)621-625
Number of pages5
JournalJournal of Endocrinology
Volume194
Issue number3
DOIs
Publication statusPublished - Sep 1 2007
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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