Objective: To investigate the effects of Huanglian Jiedu decoction (HLJD) on protein expressions and tyrosine phosphorylation levels of insulin receptor (InsR) and insulin receptor substrate-1 (IRS-1) in adipose tissue of insulin resistant (IR) rats, and explore its possible molecular mechanism in improving IR.
Methods: IR model was induced by intravenous injection of a small dose of streptozotocin combined with high fat and caloricity diet feeding in Wistar rats. And the model rats in the testing group were treated with HJD for 10 weeks. Fasting serum glucose and insulin were determined, and protein expressions and tyrosine phosphorylation levels of InsR and IRS-1 in adipose tissue of epididymides were detected by immunoprecipitation and Western blot.
Results: The protein expression of IRS-1 and the tyrosine phosphorylation levels of InsR and IRS-1 increased significantly in model rats treated with HLJD, compared with those in the untreated model rats.
Conclusion: HLJD could increase the tyrosine phosphorylation levels of InsR and IRS-1 in adipose tissue in IR rats, which maybe one of its mechanisms in lowering blood glucose and improving insulin sensitivity of the target tissues.