Comprehensive Metabolic Phenotyping Protocol

Metabolic phenotyping experiments were performed according to the EMPRESS protocols (http://empress.har.mrc.ac.uk) as previously outlined^{10 (link), 63 (link)}. Briefly, intraperitoneal glucose (2 g of glucose per kg of body weight) and insulin (0.75 U of insulin per kg of body weight) tolerance tests were performed on 16-h-fasted animals for IPGTT and 5-h-fasted animals for ITT. Glycemia was measured before and at different time after glucose and insulin injections using the Bayer Contour. Circulating insulin levels were measured using the Ultrasensitive Insulin Elisa kit (Mercodia). Oxygen consumption, carbon dioxide production, RER, food intake, and physical activity were measured continuously using Comprehensive Laboratory Animal Monitoring System (CLAMS) consisting of open circuit calorimeter and motion detectors. Body composition was measured by noninvasive quantitative MRI (EchoMRI700). ALT/SGPT Liqui-UV Test (Rate), AST/SGOT Liqui-UV Test (Rate) and Triglycerides LiquiColor™ Test (Mono) Reagents were purchased from Stanbio and used for ALT, AST and triglyceride dosage respectively.