Comparison of Plasma Active Glucagon-Like Peptide 1 Concentrations in Normal Horses and Those With Equine Metabolic Syndrome and in Horses Placed on a High-Grain Diet

Repeatability of Oral Sugar Test Results, Glucagon‐Like Peptide‐1 Measurements, and Serum High‐Molecular‐Weight Adiponectin Concentrations in Horses

“…Both aGLP‐1 and tGLP‐1 concentrations had wide 95% CIs (−8.68 to 7.86 pM and −8.52 to 6.77 pM) when Bland‐Altman analyses were performed. Lower plasma aGLP‐1 concentrations were detected in the MO‐ID group, compared to the MO‐N group, which was surprising because aGLP‐1 stimulates insulin secretion and higher concentrations were expected in horses and ponies with ID . In a study previously performed by our research group, aGLP‐1 concentrations were higher (but not significantly) during the OST in EMS horses, when compared with normal horses .…”

“…It has not been established that a SI value <1.0 × 10 −4 L/mU/min defines insulin resistance in horses and the frequently sampled intravenous glucose tolerance test procedure itself can induce stress and lower tissue insulin sensitivity . Recent studies also provide evidence that insulin status should be assessed after feeding to account for the effects of incretin hormones on insulin concentrations . Sensitivity and specificity values are not reported here because a gold standard has not been established for oral glucose tests and intravenous glucose tolerance tests do not account for the enteroinsulinar axis.…”

“…Glucose‐dependent insulinotropic peptide and glucagon‐like peptide‐1 (GLP‐1) are released from K and L cells of the intestine, respectively, and stimulate insulin secretion from beta cells in response to sugars and amino acids arriving in the intestine. Results from 2 previous studies provide evidence that active glucagon‐like peptide‐1 (aGLP‐1) concentrations are higher in hyperinsulinemic ponies and horses, when compared with normoinsulinemic controls, which suggests that incretin hormones play a role in ID . Incretin hormone concentrations are measured in the blood and might therefore serve as biomarkers for ID.…”

The diagnosis of equine insulin dysregulation

“…GLP‐1 is secreted by pancreatic L cells after ingestion of carbohydrate and increases glucose‐stimulated insulin secretion by pancreatic β cells . Plasma GLP‐1 has been shown to strongly correlate with insulin secretion in horses . However, in one study, GLP‐1 plasma concentrations did not differ between control horses and horses diagnosed with EMS, even when horses with EMS were fed a diet rich in carbohydrates .…”

“…However, in one study, GLP‐1 plasma concentrations did not differ between control horses and horses diagnosed with EMS, even when horses with EMS were fed a diet rich in carbohydrates . In other studies, horse/ponies diagnosed as insulin dysregulated on the results of an OGT had a significant increase in post‐glucose GLP‐1 . The role of GIP has been investigated less frequently in horses, but it is also secreted after the ingestion of carbohydrates.…”