Umuline

Hyperinsulinemic-euglyclemic clamps were performed in age-matched conscious unrestrained catheterized mice as previously described^{53 (link)}. Briefly, catheters were surgically implanted 7 days prior to the experiment, in the right jugular vein and exteriorized above the neck using vascular access button (Instech Laboratories Inc., Plymouth Meeting, PA). Mice were fasted for 3 h, followed by a 2-h infusion of [3-³H] glucose (0.05 μCi/min) (Perkin Elmer, Walthman, MA). Continuous insulin infusion (1.5 mIU/kg body weight/min, Umuline®, Lilly France, Neuilly-sur-Seine, France) was used for the induction of hyperinsulinemia. At reached steady state, in vivo insulin-stimulated glucose uptake in tissues was determined by a 10 μCi bolus injection of 2-[¹⁴C] deoxyglucose. After 30 min, mice were rapidly killed by cervical dislocation and tissues removed and stored at −80 °C until use. Glucose concentration was measured using the glucose oxidase method (GLU, Roche Diagnostics, Rotkreuz, Switzerland) and insulin using an ELISA commercial kit (CrystalChem Inc., Downers Grove, IL). Insulin tolerance test (ITT) was performed, as previously described^{53 (link)}. Briefly, glycemia was monitored in mice after an intraperitoneal bolus of insulin as indicated in the legend of figures representing ITT experiments.

Hyperinsulinemic–euglyclemic clamps were carried in age-matched conscious unrestrained catheterized mice as described^{84 (link),85 (link)}. To this end, catheters were surgically implanted 7 days prior to the experiment in the right jugular vein and exteriorized above the neck using a vascular access button (Instech Laboratories Inc., Plymouth Meeting, PA). Mice were fasted for 3 h, followed by an infusion for 2 h of [3-³H] glucose (0.05 μCi min⁻¹; Cat. #NET331, PerkinElmer). Continuous insulin infusion (1.5 mIU kg⁻¹ body weight min⁻¹, Umuline, Lilly France) was used for the induction of hyperinsulinemia. Upon reaching steady state, the insulin-stimulated glucose uptake in tissues was determined in vivo using a 10 μCi bolus injection of 2-[¹⁴C] deoxyglucose (Cat. #NEC720A250UC, PerkinElmer). After 30 min, mice were rapidly killed by cervical dislocation and tissues were removed and stored at –80 °C until use.
Glucose concentration was measured using the glucose oxidase method (GLU, Roche Diagnostics) and insulin using an ELISA commercial kit (Cat. #90080, CrystalChem Inc.). Measurements of 2-[¹⁴C] deoxyglucose-6-phosphate concentration in individual tissues allowed calculation of the glucose utilization index in tissues. After 30 min, tissues were removed and stored at −80 °C as above.