Abstract | BACKGROUND: Hypoadiponectinaemia is a risk factor for endocrinopathic laminitis, but the directionality and nature of its association with insulin dysregulation is unclear. OBJECTIVES: STUDY DESIGN: In vivo experiment. METHODS: Six never-laminitic, insulin-sensitive, native-breed UK ponies first underwent a dexamethasone challenge (0.08 mg/kg i.v.) with blood samples collected every 15 min over 3 h. After a 14-day washout period, hyperinsulinaemia was induced for 9 h via a euglycaemic-hyperinsulinaemic clamp (EHC), with blood samples collected every 30 min. Serum [ insulin], plasma [total adiponectin], and plasma [IGF-1] were measured using validated assays and receptor gene expression was assessed via quantitative polymerase chain reaction (qPCR). Finally, whole blood was incubated with 10-1000 ng/mL dexamethasone for 3 h at 37°C to investigate its direct effects on gene expression. RESULTS: There were no adverse effects observed during either protocol. Dexamethasone challenge did not alter circulating [ insulin] or [total adiponectin] at any time-point, but significantly upregulated AdipoR1 and IGF-1R expression at 150 and 180 min. Ex vivo incubation of whole blood with dexamethasone did not alter expression of the genes examined. There was no change in [total adiponectin] or expression of the genes examined associated with EHC-induced hyperinsulinemia. MAIN LIMITATIONS: This was a small sample size that included only native-breed ponies; total adiponectin was measured rather than high-molecular-weight adiponectin. CONCLUSIONS:
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Authors | Marine A Barnabé, Jonathan Elliott, Patricia A Harris, Nicola J Menzies-Gow |
Journal | Equine veterinary journal
(Equine Vet J)
(Oct 06 2023)
ISSN: 2042-3306 [Electronic] United States |
PMID | 37800859
(Publication Type: Journal Article)
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Copyright | © 2023 MARS Horsecare and The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd. |