Insulin-Like Growth Factor (IGF) Binding Protein-2, Independently of IGF-1, Induces GLUT-4 Translocation and Glucose Uptake in 3T3-L1 Adipocytes

Figure 3

IGFBP-2 stimulates glucose uptake in a PI3K-dependent manner. (a) Insulin, IGF-1, and IGFBP-2 increase the phosphorylation of PI3K. 3T3-L1 cells were cultured and differentiated in 24-well plates for glucose uptake assay and in 6-well plates for Western blotting analysis. The results are presented as mean ± SEM. , , and versus control. (b and c) The PI3K inhibitors, LY294002 and wortmannin (black bars), significantly reduce basal as well as insulin, IGF-1, and IGFBP-2-induced glucose uptake (white bars). Differentiated 3T3-L1 adipocytes were incubated with 100 μM LY294002 for 1 h or 200 nM wortmannin for 30 min before treatment with insulin, IGF-1, or IGFBP-2 for 30 min. The results are presented as mean ± SEM. . Each experiment was performed with three technical replicates and total number of experiments was three.

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