Glucose, Insulin, and Pyruvate Tolerance

Male and female mice (22- to 25-week-old) were placed in clean cages and food withheld for five hours. Mice were randomly assigned to treatment and control groups. 0.2 mg/kg liraglutide (Tocris) was intraperitoneally injected to the treatment group 45 minutes before the tolerance tests (-45 min). Phosphate-buffered saline (PBS) was used as a vehicle and injected in control mice at the same time. Basal glucose levels (0 min) were determined by glucometer readings (AlphaTrak^® II, Zoetisus) from tail punctures. Mice then received an intraperitoneal bolus of 2 mg/g D-Glucose (Sigma-Aldrich) for glucose tolerance tests (GTT), 0.75 IU/kg of human insulin (Actrapid 100 IU/mL, Novo Nordisk) for insulin tolerance tests (ITT) or 2 g/kg pyruvate (Sigma-Aldrich) for pyruvate tolerance tests (PTT) as in (20 (link)). Blood glucose levels were then monitored at 15, 30, 60, 90 and 120 minutes. Mice had ad libitum access to water throughout the experiment. For the sub-chronic treatment, mice received a daily intraperitoneal injection of either 0.2 mg/kg liraglutide (Tocris) or vehicle (PBS) 30 minutes before lights out for 14 days.