Value of measuring markers of lipid metabolism in horses during an oral glucose test

Background Characterizing the lipid response to an oral glucose test (OGT) might improve our understanding of Equine Metabolic Syndrome. Hypothesis/Objectives To describe the effects of an OGT on lipid metabolism and determine the value of measuring triglyceride and nonesterified fatty acid (NEFA) concentrations in hyperinsulinemic (HI) and insulin‐resistant (IR) horses. Animals Twenty horses including 7 HI‐IR horses, 4 HI‐non‐IR horses, and 9 non‐HI‐non‐IR horses (control). Methods Cross‐sectional design. Horses underwent an OGT, with blood samples collected at 0, 60, 90, and 120 minutes. Insulin, glucose, triglyceride, and NEFA concentrations were measured and compared over time and between groups, with P < .05 considered significant. Results In all horses, the OGT had a significant effect on triglyceride concentrations (median [interquartile range]: .35 [.30‐.50] mmol/L at 0 minute vs .25 [.21‐.37] mmol/L at 120 minutes, P = .005) and on NEFA concentrations (.1 [.1‐.2] mEq/L at 0 minute vs .05 [.05‐.1] mEq/L at 120 minutes, P = .0009). However, horses with HI and IR had higher triglyceride areas under the curve (AUC, 79.46 ± 46.59 vs 33.32 ± 6.75 mmol/L*min, P = .01) as well as NEFA AUC (9.1 ± 2.9 vs 6.0 ± 6.8 mEq/L*min, P = .03) than control horses. No significant difference was detected between control and HI non‐IR horses. Conclusions and Clinical Importance Determining triglyceride and NEFA concentrations might help assess tissue insulin resistance during an OGT.