Figure 1.

GR24 and pinosylvin stimulate glucose uptake and GLUT4 translocation, and GR24 upregulates GLUT4 expression. (a–f) L6 myotubes were treated with 0–100 µM test compounds for 6 h without insulin (white bars) or with 100 nM insulin (grey bars). (a,c,e) Glucose uptake was measured using [³H]2-deoxyglucose uptake assay and (b,d,f) cell surface GLUT4 was measured using in-cell western assay. (g,h) L6 myotubes were treated with 60 µM test compounds (grey bars) or with DMSO (white bar) for 24 h in media containing 5.5 mM glucose (g) or 16.7 mM glucose (h). (g,h) After western blotting, GLUT4 expression was quantified and normalised with α-tubulin detected from the same membranes after stripping and reprobing. Representative western blots are shown below. Full-length blots are presented in Supplementary information. (a–h) Bars represent the mean ± SEM of three to four independent experiments. *p < 0.05, **p < 0.01 and ***p < 0.001 between the indicated groups.