Glucose and Insulin Tolerance Tests

After two weeks of daily stress, mice received intraperitoneal glucose tolerance test (GTT) and insulin tolerance test (ITT) using standard methods^{4 (link)}. Briefly, for GTT, mice were fasted overnight and then challenged with D-glucose at 2 g/kg body weight (Sigma-Aldrich, St. Louis, MO), followed by serial measurements of blood glucose up to 120 min using a blood glucose level monitor (Glutest Ace, Sanwa Kagaku Kenkyusho Co., Nagoya, Japan). For ITT, mice were fasted for 16 hours before testing. Insulin (0.75 U/kg, Actrapid Penfill, NovoNordisk, Copenhagen, Denmark) was injected intraperitoneally, and blood glucose was measured.