Palmitic acid-rich diet suppresses glucose-stimulated insulin secretion (GSIS) and induces endoplasmic reticulum (ER) stress in pancreatic islets in mice

Takumi Hirata, Toshihide Kawai, Hiroshi Hirose, Kumiko Tanaka, Hideaki Kurosawa, Chikako Fujii, Haruhisa Fujita, Yoshiko Seto, Hideo Matsumoto, Hiroshi Itoh

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The objective was to clarify whether dietary palmitic acid supplementation affects glucose-stimulated insulin secretion (GSIS) and the endoplasmic reticulum (ER) stress pathway in pancreatic islets in mice. Eight-week-old male C57BL/6J mice were randomly divided into three treatment diet groups: control diet, palmitic acid-supplemented diet (PAL) and oleic acid-supplemented diet (OLE). After 2 weeks of treatment, intraperitoneal glucose tolerance test and intraperitoneal insulin tolerance test were performed. GSIS was assessed by pancreatic perfusion in situ with basal (100 mg/dL) glucose followed by a high (300 mg/dL) glucose concentration. We measured mRNA levels of ER stress markers such as C/EBP homologous protein (CHOP), immunoglobulin heavy-chain binding protein (BIP) and X-box binding protein (XBP)-1 using real-time polymerase chain reaction (PCR) analyses in isolated islets. Immunohistochemical staining was also performed. Mice fed PAL showed significantly decreased glucose tolerance (p < 0.05). In the perfusion study, GSIS was significantly suppressed in the PAL group (p < 0.05). Semi-quantitative RT-PCR revealed that islet CHOP, BIP, and XBP-1 mRNA expression were significantly increased in the PAL group (p < 0.05). TUNEL-positive β-cells were not detected in all groups. Dietary palmitic acid-supplementation for 2 weeks might suppress GSIS and induce ER stress in pancreatic islets in mice, in the early stage of lipotoxicity.

Original languageEnglish
Pages (from-to)8-15
Number of pages8
JournalEndocrine Research
Volume41
Issue number1
DOIs
Publication statusPublished - 2016 Jan 2
Externally publishedYes

Keywords

  • Dietary palmitic acid
  • ER stress
  • Lipotoxicity
  • β-cell

ASJC Scopus subject areas

  • Endocrinology

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