FIGURE 5.

Effects of resveratrol and metformin on AMPK activation and insulin secretion in INS-1E cells. A, INS-1E cells were treated either with 25 μm resveratrol (RSV) for 2, 6, and 24 h; with 5 mm of the AMPK activator metformin (metf.) for 24 h; and with 1 μm of the AMPK inhibitor compound C (comp.C). Levels of phosphorylated AMPK protein (pAMPK) and total AMPK were assessed by immunoblotting of INS-1E cell extracts. Total AMPK and pAMPK protein were normalized to β-actin. Immunoblotting is representative of three independent experiments. B, the secretory responses of INS-1E cells treated with resveratrol and metformin for 24 h were assayed at basal 2.5 mm and stimulatory 15 mm glucose (Glc). Values are means ± S.D. of one of three representative experiments (n = 3). *, p < 0.05; **, p < 0.01 versus 2.5 mm glucose; §§, p < 0.01 versus control at 15 mm glucose; ##, p < 0.01 versus resveratrol at 15 mm glucose.