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Diabetologia. 2009 Feb;52(2):271-80. doi: 10.1007/s00125-008-1191-9. Epub 2008 Nov 21.

A beta cell-specific knockout of hormone-sensitive lipase in mice results in hyperglycaemia and disruption of exocytosis.

Author information

1
Department of Clinical Sciences, Clinical Research Centre , Malmö University Hospital (UMAS), Malmö, Sweden. malin.fex@med.lu.se

Abstract

AIMS/HYPOTHESIS:

The enzyme hormone-sensitive lipase (HSL) is produced and is active in pancreatic beta cells. Because lipids are known to play a crucial role in normal control of insulin release and in the deterioration of beta cell function, as observed in type 2 diabetes, actions of HSL in beta cells may be critical. This notion has been addressed in different lines of HSL knockout mice with contradictory results.

METHODS:

To resolve this, we created a transgenic mouse lacking HSL specifically in beta cells, and characterised this model with regard to glucose metabolism and insulin secretion, using both in vivo and in vitro methods.

RESULTS:

We found that fasting basal plasma glucose levels were significantly elevated in mice lacking HSL in beta cells. An IVGTT at 12 weeks revealed a blunting of the initial insulin response to glucose with delayed elimination of the sugar. Additionally, arginine-stimulated insulin secretion was markedly diminished in vivo. Investigation of the exocytotic response in single HSL-deficient beta cells showed an impaired response to depolarisation of the plasma membrane. Beta cell mass and islet insulin content were increased, suggesting a compensatory mechanism, by which beta cells lacking HSL strive to maintain normoglycaemia.

CONCLUSIONS/INTERPRETATION:

Based on these results, we suggest that HSL, which is located in close proximity of the secretory granules, may serve as provider of a lipid-derived signal essential for normal insulin secretion.

PMID:
19023560
DOI:
10.1007/s00125-008-1191-9
[Indexed for MEDLINE]

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