FIG. 4.

Chronic rapamycin treatment impairs β-cell mass and insulin clearance in rats. Rats were treated with rapamycin as described in the legend to Fig. 1. Pancreatic sections were stained with an antibody against insulin for the determination of islet size and β-cell mass as described in the research design and methods section. A: Size distribution of islets expressed as percentage of total islets. n = 10 for each group. B: Pancreatic β-cell mass. n = 6 for each group. C: Plasma C-peptide levels. n = 12. D: Ratio of insulin over C-peptide, a measure of insulin clearance. n = 12 for each group. E: Insulin secretion was determined in MIN6 cells treated with rapamycin (25 nmol/l; white squares) or vehicle (black squares) for 24 h followed by glucose stimulation (10 mmol/l) for various time points. n = 3 independent experiments. *P ≤ 0.05, ***P ≤ 0.001.