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ludc web

Lena Eliasson

Principal investigator

ludc web

Long-term exposure of mouse pancreatic islets to oleate or palmitate results in reduced glucose-induced somatostatin and oversecretion of glucagon

Author

  • S. C. Collins
  • S Albert Salehi
  • Lena Eliasson
  • C. S. Olofsson
  • P. Rorsman

Summary, in English

Aims/hypothesis Long-term exposure to NEFAs leads to inhibition of glucose-induced insulin secretion. We tested whether the release of somatostatin and glucagon, the two other major islet hormones, is also affected. Methods Mouse pancreatic islets were cultured for 72 h at 4.5 or 15 mmol/l glucose with or without 0.5 mmol/l oleate or palmitate. The release of glucagon and somatostatin during subsequent 1 h incubations at 1 or 20 mmol/l glucose as well as the islet content of the two hormones were determined. Lipid-induced changes in islet cell ultrastructure were assessed by electron microscopy. Results Culture at 15 mmol/l glucose increased islet glucagon content by similar to 50% relative to that observed following culture at 4.5 mmol/l glucose. Inclusion of oleate or palmitate reduced islet glucagon content by 25% (at 4.5 mmol/l glucose) to 50% (at 15 mmol/l glucose). Long-term exposure to the NEFA increased glucagon secretion at 1 mmol/l glucose by 50% (when islets had been cultured at 15 mmol/l glucose) to 100% (with 4.5 mmol/l glucose in the culture medium) and abolished the inhibitory effect of 20 mmol/l glucose on glucagon secretion. Somatostatin content was unaffected by glucose and lipids, but glucose-induced somatostatin secretion was reduced by similar to 50% following long-term exposure to either of the NEFA, regardless of whether the culture medium contained 4.5 or 15 mmol/l glucose. Ultrastructural evidence of lipid deposition was seen in < 10% of non-beta cells but in > 80% of the beta cells. Conclusions/interpretation Long-term exposure to high glucose and/or NEFA affects the release of somatostatin and glucagon. The effects on glucagon secretion are very pronounced and in type 2 diabetes in vivo may aggravate the hyperglycaemic effects due to lack of insulin.

Department/s

  • Islet cell physiology
  • Diabetes - Islet Cell Exocytosis

Publishing year

2008

Language

English

Pages

1689-1693

Publication/Series

Diabetologia

Volume

51

Issue

9

Document type

Journal article

Publisher

Springer

Topic

  • Endocrinology and Diabetes

Keywords

  • palmitate
  • oleate
  • NEFA
  • glucolipotoxicity
  • diabetes
  • glucagon
  • somatostatin

Status

Published

Research group

  • Islet cell physiology
  • Diabetes - Islet Cell Exocytosis

ISBN/ISSN/Other

  • ISSN: 1432-0428