FIGURE 1.

A, mature SGBS adipocytes were treated with IFNγ (20 ng/ml), or control (SFM+0.2% BSA), for the indicated time points prior to stimulation with insulin (100 nm) for 15 min. [³H]Glucose uptake was monitored over a further 15-min period. Fold-increase in insulin-stimulated [³H]glucose uptake over basal (non-insulin treated cells) is presented (n = 4, ***, p < 0.001 versus insulin alone). B, mature SGBS adipocytes were treated with increasing concentrations of IFNγ (in SFM + 0.2% BSA) for 48 h and insulin-stimulated [³H]glucose uptake subsequently monitored. Fold-increase in insulin-stimulated glucose uptake over basal is presented (*, p < 0.05; **, p < 0.01; ***, p < 0.001 versus insulin alone, n = 3). C, SGBS adipocytes were treated with IFNγ for the indicated time points and the effects on mRNA expression of insulin signaling genes was measured by real-time PCR analysis (n = 3, **, p < 0.01; ***, p < 0.001 versus control; white circles, insulin receptor; black squares, insulin receptor substrate 1; black triangles, Glut4). Error bars represent S.E. D, adipocyte protein lysates from time course glucose uptake assay were probed for levels of phosphorylated AKT and whole cell AKT by immunoblot analysis. E, the effect of IFNγ on protein levels of IRS1 and β-actin was assessed by immunoblot analysis.