Fig. 2From: Effects of unaltered and bioconverted mulberry leaf extracts on cellular glucose uptake and antidiabetic action in animalsComparison of the abilities of bioconverted mulberry leaf extract (BMLE) and unaltered mulberry leaf extract (MLE) to improve glucose uptake and insulin secretion in (a) differentiated C2C12 myotubes, (b) 3 T3-L1 adipocytes, and (c) HIT-T15 pancreatic β-cells. To measure glucose uptake, cells were incubated in serum-starved DMEM for 1 h and then, treated with MLE, BMLE or rosiglitazone (Rg) for 1 h. The medium was changed to Krebs-Ringer phosphate-HEPES buffer containing the prescribed concentrations of MLE, BMLE or Rg for 30 min and then treated with 100 nM insulin for 30 min. After treatment with 2-deoxy-[3H]–glucose (0.5 μCi/mL) and 2-deoxy-D-glucose (100 μM) for 10 min, the reaction was terminated and glucose uptake activity was measured in lysed cells with a liquid scintillation counter (see Materials and methods). To measure insulin secretion, cells incubated with Krebs-Ringer bicarbonate-HEPES buffer containing 0.3% bovine serum albumin for 30 min were treated with 11.1 mM glucose and MLE, BMLE or glimepiride (GLM) for 1 h and the insulin concentration released into the media was measured (see Materials and Methods). Rg (10 μM) and GLM (1 μg/mL) were used as positive controls for glucose uptake in differentiated C2C12 myotubes and 3 T3-L1 adipocytes and insulin release in HIT-T15 pancreatic β-cells, respectively. Data are expressed as the mean ± SEM of three independent experiments. * P < 0.05 and ** P < 0.01 versus insulin-stimulated glucose uptake or glucose-stimulated insulin release in the untreated control; # P < 0.05 and ## P < 0.01 versus insulin-stimulated glucose uptake or glucose-stimulated insulin release in the MLE-treated groupBack to article page