Short-term induced hyperinsulinaemia and dexamethasone challenge do not affect circulating total adiponectin concentrations in insulin-sensitive ponies.
Equine Vet J
; 56(2): 332-341, 2024 Mar.
Article
en En
| MEDLINE
| ID: mdl-37800859
ABSTRACT
BACKGROUND:
Hypoadiponectinaemia is a risk factor for endocrinopathic laminitis, but the directionality and nature of its association with insulin dysregulation is unclear.OBJECTIVES:
To investigate the effects of short-term induced hyperinsulinaemia and dexamethasone challenge on circulating [total adiponectin] and whole blood expression of adiponectin (AdipoR1 and AdipoR2), insulin, and insulin-like growth factor 1 (IGF-1) receptors in insulin-sensitive ponies. STUDYDESIGN:
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. MAINLIMITATIONS:
This was a small sample size that included only native-breed ponies; total adiponectin was measured rather than high-molecular-weight adiponectin.CONCLUSIONS:
Short-term induced hyperinsulinaemia and dexamethasone challenge did not affect circulating [total adiponectin] in insulin-sensitive ponies. However, dexamethasone administration was associated with upregulation of two receptors linked to adiponectin signalling, suggesting that a physiological response occurred possibly to counteract dexamethasone-associated changes in tissue insulin sensitivity.Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Enfermedades del Pie
/
Pezuñas y Garras
/
Enfermedades de los Caballos
/
Hiperinsulinismo
Tipo de estudio:
Diagnostic_studies
/
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
Equine Vet J
Año:
2024
Tipo del documento:
Article
País de afiliación:
Reino Unido