FIG. 3.

ROS mediate insulin signaling in A. stephensi cells in vitro. (A) Pretreatment with the antioxidant MnTBAP reduced insulin-induced MAPK and PI3K/Akt signaling. ASE cells were treated with 5 μM MnTBAP (MnT) for 40 min before stimulation with 1.7 μM human insulin for 5 min. Cell lysates were analyzed by western blotting with anti-phospho-specific antibodies. The effects of MnTBAP pretreatment on MEK, ERK, and p38 phosphorylation (A, C), as well as FOXO and p70S6K phosphorylation (B, D) are shown. Fold changes in phospho-specific proteins in pairwise comparisons of treatments or of treatments and PBS-treated controls from three independent experiments were analyzed with Student's t-test (α = 0.05). GAPDH provided an assessment of protein loading and were used to normalize corresponding phospho-protein levels. Data are represented as means ± SEMs and significant differences are indicated. MAPK, mitogen-activated protein kinase; PI3K, phosphatidylinositol 3-kinase; ERK, extracellular signal-regulated kinase; FOXO, forkhead box O1; MEK, mitogen activated protein kinase kinase.