Optimisation of the frequently sampled intravenous glucose tolerance test to reduce urinary glucose spilling in horses.

The research article investigates ways to improve the frequently sampled intravenous glucose tolerance test (FSIGTT) in horses. One of the goals was to determine the impact of urinary glucose spilling (UGS) on the test results. The researcher expanded the existing test protocol by altering the dextrose and insulin dosages used. They concluded that reducing the dextrose dosage to 100 mg/kg bwt can lessen UGS. They recommend a new FSIGTT using this lowered dextrose dosage, followed by an insulin dosage 20 minutes later.

Study Methodology

• Six adult mares were included in this study.
• In the first phase, each horse underwent 6 FSIGTT procedures to evaluate varying dextrose dosages.
• In the second phase, 6 different insulin dosages were evaluated for each horse. Before administering these dosages, each horse was given 300 mg/kg bwt dextrose.
• The area under the glucose (AUCg) and insulin (AUCi) curves were calculated, and minimal model analyses were conducted.
• In the third and fourth phases, UGS was measured during the combined glucose insulin test and during the original FSIGTT. A new FSIGTT was then introduced and evaluated based on these measurements.

Results

• The researchers observed positive linear effects of dextrose dosage on AUCg, AUCi, and the acute insulin response to glucose. AUCg plateaued at dextrose dosages above 200 mg/kg bwt.
• The insulin dosages had an inverse linear impact on AUCg, but didn’t significantly affect any other aspects.
• UGS was noticed during all 3 tests and was highest for the original FSIGTT and lowest for the new FSIGTT.
• The type of FSIGTT carried out didn’t influence the results of the minimal model analysis.

Conclusions

• The current dextrose dosage of 300 mg/kg bwt used in the established FSIGTT appears to be too high, according to the study’s findings.
• UGS can be minimized by lowering the dextrose dosage to 100 mg/kg bwt.
• The researchers suggest a new FSIGTT involving a dextrose dosage of 100 mg/kg bwt, followed by an insulin dosage of 20 mu/kg bwt 20 minutes later. This test protocol provides adequate data for minimal model analysis while reducing UGS.