Glucose tolerance and insulin tolerance during aging in C57BL/6 mice.

<p>(A) Glucose tolerance tests (GTT) were performed in different groups of mice at different ages (4, 8, 12, 16, and 20 months of age) by intraperitoneal injection of glucose (2 g/kg, i.p.) and changes in blood glucose concentration were monitored at the indicated time points. (C) Insulin tolerance tests (ITT) were performed after insulin injection (1 U/kg, i.p.). Area under the curve (AUC) was calculated as mg·dl^-1·min based on the GTT (B) and ITT curves (D). n = 5–7 per group, Data are means ± SD. *p < 0.05 <i>vs</i>. 4-month-old mice.