Figure 3

Glucose uptake and lipolysis in murine 3T3-L1 adipocytes. (a,b) Glucose uptake was quantified by fluorescent 2-NBD-glucose uptake (100 μg/mL, 20 min incubation with/without 100 nM insulin (Ins)) in DMEM (1 g/L glucose) following overnight serum-starvation and 2 h incubation with/without 100 µM acylcarnitines (including 1 h in glucose-free DMEM). Intracellular fluorescence is expressed in relation to basal uptake in the control cells. Differences in glucose uptake between basal and insulin-stimulated conditions are shown in boxplots (a); panel (b) shows individual conditions from the same experiments. (c,d) Lipolysis was measured in overnight serum-starved cells in DMEM over 1 h with/without exposure to 100 nM isoproterenol (Iso) ± 10 nM Ins. Cells were pre-incubated for 2 h with vehicle or 100 µM acylcarnitines. Cell density-normalized glycerol release is shown as the difference in glycerol release after insulin stimulation in panel (c), individual conditions in the same experiments are shown in panel (d). Experiments were reproduced in replicates for glucose uptake (n = 3 experiment) or triplicates for lipolysis (n = 2 per experiment) and combined results are shown. P-values are from two-tailed t-tests; error bars indicate standard errors.