Figure 4

Effect of BBR metabolites on InsR, LDLR and AMPK. HepG2 cells were respectively treated with the compounds for 8 hrs at concentration of 20 μM for InsR test or 40 μM for LDLR, followed by RNA extraction and real time RT-PCR assay for the InsR or LDLR mRNA. The amount of LDLR (a) and InsR (b) mRNA in the treated cells was normalized to that of the untreated control. * p < 0.05, **p < 0.01, vs the untreated control. To detect the protein expression, HepG2 cells were treated with BBR (27 μM) for 8 hrs, with simvastatin (1 μM) and rosiglitazone(10 μM) as references. Berberine increased the cell-surface expression of both InsR and LDLR in the hepatocytes (c). For AMPK activation, HepG2 cells were treated with the study compounds (20 μM) for 24 hrs with DMSO as a control. AMPK-alpha phosphorylation in the HepG2 cells was detected with immunoblots, using a protocol described in the Methods (d).