Performing Dual Glucose Clamp Experiments in Sedated Farm Swine: A Practical Method

The hyperinsulinemic-euglycemic clamp technique is considered the gold standard for measuring insulin sensitivity in large animals. We developed a practical method for conducting concurrent glucose clamp experiments in a pair of sedated farm swine positioned in a sling. Descriptions of customized equipment and central venous access surgical procedures for blood collection are provided. Personnel functions are described for execution of the clamp protocol. A total of 24 hyperinsulinemic-euglycemic clamp studies were performed over 6 weeks. Infusaports remained functional for 1454 blood samples. There were three CSII catheter occlusions during bolus administration, and the swine showed no signs of infection or disease. IM telazol at 1.0 mg/kg, administered 1-2 h prior (mean of 3.26 mL ± 1.59) was effective in keeping animals comfortable. SpO₂ and heart rate remained within normal ranges. Means ± SD total infused volumes for octreotide, 10% dextrose, and saline were 9.7 ± 0.93 mL, 2328.0 ± 672.8 mL, and 690.3 ± 206.8 mL. Mean blood glucose was maintained between 75.7 and 87.8 mg/dL (CV 3.17%) for the 24 experiments. The GIR infusion rate peaked between 15 and 60 min after insulin bolusing, with insulin C_max of 108.5 pmol/L and t_max at 10 min. All aspects of the protocol were effectively carried out. The animals remained in good health, and the implanted infusion ports remained patent for over 700 blood draws per animal. This method could potentially reduce the number of animals used and the costs of other similar experiments.