D glucose

The intraperitoneal glucose and insulin tolerance tests (IPGTT and ITT) were conducted at weeks 7 and 8, respectively. In brief, mice were either fasted overnight or for 6 h, and then received an intraperitoneal injection of single-dose D-glucose (1.0 g/kg) or insulin (0.75 UI/kg; Novo Nordisk). Blood from the caudal vein was collected at 0, 15, 30, 60, and 120 min, respectively. A glucometer (Yuwell, Jiangsu, China) was used to measure blood glucose levels. Concentrations of fasting blood glucose and fasting serum insulin were measured, and the homeostasis model index of insulin resistance (HOMA-IR) was calculated according to the formula: HOMA-IR = insulin×glucose/22.5, as previously [25 (link)].

For the intraperitoneal glucose tolerance test (IPGTT) and insulin tolerance test (ITT), mice were fasted overnight and then given an intraperitoneal injection of D-glucose (1.5 g/kg) or insulin (0.75 UI/kg; Novo Nordisk). Blood samples were harvested from the tail vein at different time points, and the blood glucose was measured using a glucometer (Johnson & Johnson, Shanghai, China). After testing serum fasting blood glucose and insulin concentrations, we calculated the homeostasis model index of insulin resistance (HOMA-IR: insulin × glucose/22.5) and the quantitative insulin sensitivity check index (QUICKI: 1/[log (insulin) + log (glucose)]), as previously described [49 (link)].