The target clamp blood glucose level was determined for each animal to be equal to its own basal blood glucose level (average of at least 3 stable consecutive samples over a 20 min period commencing at least 130 min after completion of surgery). Human insulin (Actrapid, Novo Nordisk, Bagsvaerd, Denmark) was infused at a constant rate based on lean body mass estimated according to [17] via a dedicated jugular vein catheter using a syringe pump (CMA 1100, Carnegie Medicin, Solna, Sweden). Arterial blood glucose was measured every 5 min using a glucose analyzer (YSI Incorporated, Yellow Springs, OH, USA; 15 μL blood per sample). Blood glucose was clamped at the basal level (isoglycemia) with a variable rate infusion of 20% (w : v) glucose, using a syringe pump (Model 22 I/W, Harvard Apparatus Inc., South Natic, MA, USA) via a dedicated jugular vein catheter. Steady state in both blood glucose level (within ±10% of the target level) and glucose infusion rate (GIR) was generally achieved within 60 min of clamp start.
