Measurement of C-peptide concentrations and responses to somatostatin, glucose infusion, and insulin resistance in horses.
Authors: Tóth F, Frank N, Martin-Jiménez T, Elliott S B, Geor R J, Boston R C
Journal: Equine veterinary journal
Summary
# Editorial Summary: C-peptide as a marker of pancreatic insulin secretion in equine insulin resistance Elevated insulin concentrations are commonly observed in insulin-resistant horses, yet the underlying mechanism—whether from increased pancreatic secretion or reduced hepatic clearance—remained unclear until this investigation. Tóth and colleagues measured C-peptide alongside insulin in response to somatostatin suppression, glucose infusion, and insulin tolerance testing, exploiting C-peptide's equimolar secretion with insulin and resistance to hepatic metabolism as a more reliable indicator of pancreatic function than insulin alone. The findings demonstrated that hyperinsulinaemia in insulin-resistant horses reflects genuine pancreatic oversecretion rather than impaired insulin clearance, with C-peptide concentrations accurately reflecting the pancreatic response across all provocative tests. For equine practitioners, this validates C-peptide measurement as a superior diagnostic tool for distinguishing true insulin resistance from other metabolic disturbances, offering more physiologically meaningful assessment of pancreatic beta-cell dysfunction in cases of equine metabolic syndrome and laminitis risk. Understanding this distinction refines diagnostic accuracy and may better guide nutritional and pharmaceutical management strategies in predisposed horses.
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Practical Takeaways
- •C-peptide testing offers a more accurate assessment of pancreatic beta-cell function than insulin alone in horses suspected of insulin resistance, helping distinguish true hyperinsulinaemia from other metabolic issues
- •This measurement tool can improve diagnostic accuracy for equine metabolic syndrome and insulin resistance, informing better management and treatment decisions
- •Understanding C-peptide responses helps veterinarians evaluate horses with conditions associated with insulin resistance, such as laminitis and obesity
Key Findings
- •C-peptide measurement provides a reliable indicator of pancreatic insulin secretion in horses, as it is secreted equimolarly with insulin and not cleared by the liver
- •The study validated C-peptide concentration responses to somatostatin, glucose infusion, and insulin resistance as a diagnostic approach in equine patients
- •C-peptide assessment can differentiate between true pancreatic hyperinsulinaemia and other causes of elevated circulating insulin in horses