Equine hyperinsulinemia: Investigation of the enteroinsular axis during insulin dysregulation

de Laat, Melody A., McGree, James M., & Sillence, Martin N. (2016) Equine hyperinsulinemia: Investigation of the enteroinsular axis during insulin dysregulation. American Journal of Physiology - Endocrinology and Metabolism, 310(1), E61-E72.

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Compared to other species insulin dysregulation in equids is poorly understood. Hyperinsulinemia causes laminitis, a significant and often lethal disease affecting the pedal bone/hoof wall attachment site. Until recently, hyperinsulinemia has been considered a counter-regulatory response to insulin resistance (IR), but there is growing evidence to support a gastrointestinal etiology. Incretin hormones released from the proximal intestine, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide, augment insulin secretion in several species, but require investigation in horses. This study investigated peripheral and gut-derived factors impacting insulin secretion by comparing the response to intravenous (IV) and oral D-glucose. Oral and IV tests were performed in 22 ponies previously shown to be insulin dysregulated, of which only 15 were classified as IR (IV test). In a more detailed study, nine different ponies received four treatments: D-glucose orally, D-glucose IV, oats and Workhorse-mix. Insulin, glucose and incretin concentrations were measured before and after each treatment. All nine ponies showed similar IV responses, but five were markedly hyper-responsive to oral D-glucose and four were not. Insulin responsiveness to oral D-glucose was strongly associated with blood glucose concentrations and oral glucose bioavailability, presumably driven by glucose absorption/distribution, as there was no difference in glucose clearance rates. Insulin was also positively associated with active GLP-1 following D-glucose and grain. This study has confirmed a functional enteroinsular axis in ponies which likely contributes to insulin dysregulation that may predispose them to laminitis. Further, IV tests for IR are not reliable predictors of the oral response to dietary non-structural carbohydrate.

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4 citations in Scopus
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3 citations in Web of Science®

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ID Code: 91059
Item Type: Journal Article
Refereed: Yes
Keywords: insulin, incretin, glucagon-like peptide-1, glucose, horse
DOI: 10.1152/ajpendo.00362.2015
ISSN: 1522-1555
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > PHYSIOLOGY (060600) > Animal Physiology - Systems (060603)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > CLINICAL SCIENCES (110300) > Endocrinology (110306)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > Schools > School of Mathematical Sciences
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Copyright Owner: Copyright 2015 American Journal of Physiology - Endocrinology and Metabolism
Deposited On: 07 Dec 2015 23:59
Last Modified: 06 Jan 2016 07:40

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