FIG. 4.

Plasmid-derived expression of IGF-I in liver normalizes β-cell mass, insulinemia, and glucose tolerance. TUNEL-positive (apoptotic) (A) and Ki67-positive (replicative) (B) β cells were counted 2 weeks after STZ injection as indicated in research design and methods. Results are mean ± SEM of four mice per group. *P < 0.05 vs. controls (Con). #P < 0.05 vs. STZ-Con. C: β-cell mass was measured 4 months after STZ administration. Serum insulin levels (D) and glucose tolerance (E) were measured 7 weeks after the first IGF-I administration. Results are mean ± SEM of four to five mice per group. For glucose tolerance test, blood glucose levels were measured after an intraperitoneal glucose injection of 1 g/kg body weight. *P < 0.05 vs. Con. Data are representative of three independent experiments.