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Proc Natl Acad Sci U S A. 2012 Jun 12;109(24):9641-6. doi: 10.1073/pnas.1201433109. Epub 2012 May 22.

Apolipoprotein A-IV improves glucose homeostasis by enhancing insulin secretion.

Author information

1
Departments of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, OH 45237, USA.

Abstract

Apolipoprotein A-IV (apoA-IV) is secreted by the small intestine in response to fat absorption. Here we demonstrate a potential role for apoA-IV in regulating glucose homeostasis. ApoA-IV-treated isolated pancreatic islets had enhanced insulin secretion under conditions of high glucose but not of low glucose, suggesting a direct effect of apoA-IV to enhance glucose-stimulated insulin release. This enhancement involves cAMP at a level distal to Ca(2+) influx into the β cells. Knockout of apoA-IV results in compromised insulin secretion and impaired glucose tolerance compared with WT mice. Challenging apoA-IV(-/-) mice with a high-fat diet led to fasting hyperglycemia and more severe glucose intolerance associated with defective insulin secretion than occurred in WT mice. Administration of exogenous apoA-IV to apoA-IV(-/-) mice improved glucose tolerance by enhancing insulin secretion in mice fed either chow or a high-fat diet. Finally, we demonstrate that exogenous apoA-IV injection decreases blood glucose levels and stimulates a transient increase in insulin secretion in KKAy diabetic mice. These results suggest that apoA-IV may provide a therapeutic target for the regulation of glucose-stimulated insulin secretion and treatment of diabetes.

PMID:
22619326
PMCID:
PMC3386109
DOI:
10.1073/pnas.1201433109
[Indexed for MEDLINE]
Free PMC Article

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