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

Collins, S. C.; Salehi, S Albert LU ; Eliasson, Lena LU ; Olofsson, C. S. and Rorsman, P. (2008) In Diabetologia 51(9). p.1689-1693
Abstract
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... (More)
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. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
palmitate, oleate, NEFA, glucolipotoxicity, diabetes, glucagon, somatostatin
in
Diabetologia
volume
51
issue
9
pages
1689 - 1693
publisher
Springer Verlag
external identifiers
  • wos:000258236200019
  • scopus:49249115161
ISSN
1432-0428
DOI
10.1007/s00125-008-1082-0
language
English
LU publication?
yes
id
5f55f4fd-5aaa-41c3-9157-1e4b55bed481 (old id 1253466)
date added to LUP
2008-11-14 14:44:29
date last changed
2017-07-09 03:44:44
@article{5f55f4fd-5aaa-41c3-9157-1e4b55bed481,
  abstract     = {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 &lt; 10% of non-beta cells but in &gt; 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.},
  author       = {Collins, S. C. and Salehi, S Albert and Eliasson, Lena and Olofsson, C. S. and Rorsman, P.},
  issn         = {1432-0428},
  keyword      = {palmitate,oleate,NEFA,glucolipotoxicity,diabetes,glucagon,somatostatin},
  language     = {eng},
  number       = {9},
  pages        = {1689--1693},
  publisher    = {Springer Verlag},
  series       = {Diabetologia},
  title        = {Long-term exposure of mouse pancreatic islets to oleate or palmitate results in reduced glucose-induced somatostatin and oversecretion of glucagon},
  url          = {http://dx.doi.org/10.1007/s00125-008-1082-0},
  volume       = {51},
  year         = {2008},
}