Figure 1

Glucose homeostasis in young (2-month-old) and old (12-month-old) WT and PARP-1^−/− mice. Intraperitoneal glucose tolerance test in young and old mice (n = 4–5) before (A) and after (C) a single administration of low-dose (90 mg/kg) STZ. Mice fasted overnight before testing, and levels of blood glucose were measured before and after glucose challenge (2 mg glucose/g body weight). *p < 0.05, **p < 0.01 versus old PARP-1^−/− mice. Insulin secretion by determining blood insulin levels in the glucose tolerance test before (E) and after (G) STZ. **p < 0.01 versus old WT mice. Blood glucose levels of young and old mice (n = 4–5) after overnight fasting before (B) and after (D) STZ. Blood insulin levels of young and old mice (n = 4–5) after overnight fasting before (F) and after (H) STZ. **p < 0.01 versus old WT mice.