Automated glucometer

Blood samples were collected from the tail vein of the animals after they had fasted for 12 h, while they were still awake. Blood glucose levels during fasting were measured using an automated glucometer by Roche. Adhering to the supplied protocols, fasting insulin (FINS) levels were determined with a rodent insulin ELISA kit (Thermo Fisher Scientific, Catalog # ERINS), and testosterone concentrations were quantified using a Testosterone Parameter Assay Kit (R&D Systems, Catalog # KGE010).

Food intake and body weight were measured once a week. Briefly, for the glucose tolerance test (GTT), mice which were fasted overnight were injected (i.p.) with D-glucose (1 g/kg body weight; Sigma-Aldrich) after 12 h fasting. For the insulin tolerance test (ITT), mice were injected (i.p.) with insulin (0.75 units/kg body weight; Novolin R, Novo Nordisk, Copenhagen, Denmark) after 6 h fasting. Glucose concentrations were measured in tail venous blood using an automated glucometer (Roche Diagnostics) up to 90 min or 120 min after injection.
Fasting insulin was measured by the insulin ELISA kit (Cusabio, Wuhan, China). Liver concentrations of triglyceride (TG) was measured by the triglyceride assay kit (Nanjing Jiancheng Bioengineering Institute, Nanjing, China). Serum concentrations of total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), apolipoprotein E (ApoE), FFA and hsCRP were measured by enzymatic method using an automatic biochemical analyzer (Beckman AU5800, USA).

In GTT, mice were fasted for 12 hours and injected intraperitoneally with 1 g/kg body weight dextrose (Sigma). In ITT, after fasting for 6 hours, intraperitoneal 0.75 units/kg body weight insulin (Sigma) injection was performed. Glucose levels were detected from tail venous blood with an automated glucometer (Roche) at 0 min, 15 min, 30 min, 60 min, 90 min, 120 min after injection, which was also described in our previous study [30 (link)].