Fig. 1.

STZ reduces body weight, serum insulin levels, and IR phosphorylation, but enhances blood glucose levels. Three-month-old Tg2576 mice were fasted for 4 h and intraperitoneally (i.p.) injected with STZ (50 mg/kg) or sodium citrate solution only (vehicle control) once a day for 5 consecutive days. A Body weight and B blood glucose levels were monitored at 1, 4, 8, 12, and 16 weeks after STZ administration (n = 11 per group). C Sixteen weeks after STZ administration, mice were sacrificed and serum insulin levels were measured using ELISA (n = 10 per group). D Protein levels of total (t-) and phosphorylated (p-) insulin receptor (IR) in the cortex of mice (n = 6 per group) were determined by Western blotting and quantified by densitometry. Quantification of the t-IR and p-IR levels normalized to actin and t-IR levels, respectively, expressed as values relative to the vehicle control. All values are presented as the mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001, as determined by Student’s t test