Impaired postprandial releases/syntheses of ghrelin and PYY3-36 and blunted responses to exogenous ghrelin and PYY3-36 in a rodent model of diet-induced obesity

Junying Xu, Terry A. Mcnearney, Jdz Chen

Research output: Contribution to journalArticlepeer-review


Background and Aim: This study investigated the effects of peripheral administration of ghrelin and PYY3-36 on food intake and plasma and tissue fasting and postprandial ghrelin and PYY3-36 levels in normal-weight (NW) and diet-induced-obese (DIO) rats. Methods: In experiment one, NW and DIO rats received a single intraperitoneal injection of saline, PYY3-36 or ghrelin; food intake was measured for 4h. In experiment two, total plasma ghrelin and PYY3-36, gastric fundus ghrelin, and ascending colon PYY3-36 were measured either after a 20-h fast or 2h after refeeding in NW and DIO rats by radioimmunoassay. Results: Compared to the NW rats, findings in the DIO rats revealed: (i) a reduced sensitivity to both the anorectic effect of exogenous PYY3-36 and the orexigenic effect of exogenous ghrelin; (ii) the postprandial plasma ghrelin levels were significantly higher; and (iii) refeeding decreased endogenous plasma ghrelin levels by 53% in the NW rats and 39% in DIO rats. Refeeding increased the plasma PYY3-36 level by 58% in the NW rats versus 9% in the DIO rats (P=0.003). Conclusions: Compared with regular rats, DIO rats exhibit blunted responses in food intake to exogenous ghrelin and PYY3-36. Although endogenous ghrelin and PYY3-36 in DIO rats are not altered in the fasting state, their responses to food ingestion are blunted in comparison with regular rats.

Original languageEnglish (US)
Pages (from-to)700-705
Number of pages6
JournalJournal of Gastroenterology and Hepatology (Australia)
Issue number4
StatePublished - Apr 2011
Externally publishedYes


  • Diet-induced obesity
  • Food response
  • Ghrelin
  • PYY

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

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