Temporal variation in incretin and insulin secretion in ponies in association with dietary macronutrients.
Authors: Andrews K E, Sibthorpe P E M, Fitzgerald D M, de Laat M A
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Insulin dysregulation represents a significant clinical challenge in equine practice, with hyperinsulinaemia driving laminitis risk, yet the underlying mechanisms remain incompletely understood. Andrews and colleagues investigated the temporal dynamics of two key incretin hormones—glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)—alongside insulin and glucose across a 24-hour period in eight healthy ponies fed a high-fibre ration, with findings subsequently validated in a larger cohort of 30 animals using archived serum samples. Blood glucose, GLP-1 and insulin demonstrated strong synchronous correlation (ρ approaching 1.0), all peaking postprandially, whilst GIP showed unexpected elevation in the fasted state and a significant positive relationship with serum triglycerides (r = 0.39; P = 0.03 in the larger cohort). These results suggest GIP functions primarily in lipid metabolism and fat clearance in ponies, distinct from its glucose-regulatory role, indicating that future investigation into GIP's contribution to metabolic dysfunction and obesity-associated laminitis risk could refine dietary and pharmacological management strategies for insulin-dysregulated animals. The synchronous GLP-1–insulin relationship substantiates the hypothesis that incretin dysregulation may contribute to pathological insulin secretion in predisposed individuals, offering potential targets for therapeutic intervention.
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Practical Takeaways
- •Understanding the role of GIP in fat metabolism may help manage obese ponies and those at risk of laminitis through targeted dietary interventions
- •The strong postprandial response of insulin and GLP-1 to feeding suggests that meal timing and composition are critical factors in managing insulin dysregulation
- •Monitoring triglyceride levels may provide practical insight into GIP-mediated metabolic dysfunction in at-risk horses
Key Findings
- •Blood glucose, GLP-1 and insulin showed strong positive synchronous correlation (ρ close to 1) with peaks occurring after feeding
- •GIP concentration peaked in the unfed state and was positively correlated with triglyceride concentration (r=0.39; P=0.03 in larger cohort)
- •GIP likely has a physiological role in lipid clearance and fat metabolism in ponies, similar to other species
- •All analytes (glucose, protein, triglycerides, GLP-1, GIP, insulin) demonstrated significant temporal variation over 24 hours (P<0.05)