Associations between feeding and glucagon‐like peptide‐2 in healthy ponies

Abstract

AbstractBackgroundGastrointestinal peptides, such as glucagon‐like peptide‐2 (GLP‐2), could play a direct role in the development of equine hyperinsulinaemia.ObjectivesTo describe the secretory pattern of endogenous GLP‐2 over 24 h in healthy ponies and determine whether oral administration of a synthetic GLP‐2 peptide increases blood glucose or insulin responses to feeding.Study DesignA cohort study followed by a randomised, controlled, cross‐over study.MethodsIn the cohort study, blood samples were collected every 2 h for 24 h in seven healthy ponies and plasma [GLP‐2] was measured. In the cross‐over study, 75 μg/kg bodyweight of synthetic GLP‐2, or carrier only, was orally administered to 10 ponies twice daily for 10 days. The area under the curve (AUC0–3h) of post‐prandial blood glucose and insulin were determined before and after each treatment.ResultsEndogenous [GLP‐2] ranged from <0.55 to 1.95 ± 0.29 [CI 0.27] ng/mL with similar peak concentrations in response to meals containing 88–180 g of non‐structural carbohydrate, that were ~4‐fold higher (P < 0.001) than the overnight nadir. After GLP‐2 treatment peak plasma [GLP‐2] increased from 1.1 [0.63–1.37] ng/mL to 1.54 [1.1–2.31] ng/mL (28.6%; P = 0.002), and AUC0–3h was larger (P = 0.01) than before treatment. The peptide decreased (7%; P = 0.003) peak blood glucose responses to feeding from 5.33 ± 0.45 mmol/L to 5.0 ± 0.21 mmol/L, but not AUC0–3h (P = 0.07). There was no effect on insulin secretion.Main LimitationsThe study only included healthy ponies and administration of a single dose of GLP‐2.ConclusionsThe diurnal pattern of GLP‐2 secretion in ponies was similar to other species with no apparent effect of daylight. Although GLP‐2 treatment did not increase post‐prandial glucose or insulin responses to eating, studies using alternative dosing strategies for GLP‐2 are required.