Objective To observe the influence of serum containin g Jiangzhi Pinggan Decoction（Decoction for lowering lipid and calming the liver） on the expressio n of insulin receptor substrate-1（IRS-1） mRNA and peroxisome proliferator-ac tivated receptor γ（PPAR-γ） mRNA in 3T3-L1 adipocytes in rats and discuss its mecha nism.Methods Sixteen Wistar rat were selected.The 3T3-L1 preadipocytes were cultured in vitro and differentia ted to adipocytes.The cell model of insulin resistance（IR） was induced by tumor necrosi s factor-α（TNF-α）.The control group was established by adding 20% o f blank serum to the culture medium.The model group was established by adding 20n g/ml of TNF-α on the basis of the control group.The rosiglitazone group and J iangzhi Pinggan group was added the corresponding bbc-containing serum respectiv ely besides the culture medium and 20ng/ml of TNF-α.The expression of IRS-1 mRN A and PPAR-γ mRNA was observed after culturing for 48 hours.R esults Comparing with the control group

the expression of IRS-1 mRNA and PPAR-γ mRNA was sign ificantly decreased in the model group（P<0.05）.The expression of IRS-1 mRN A and PPAR-γ mRNA in the rosiglitazone group was similar to that in the Jiangzhi Pin ggan Decoction group

but the differences were statistically significant between the model group and both medication groups（P<0.05）.Conclu sion Jiangzhi Pinggan Decoction could inhibit the IR of 3T3-L1 adipocytes

which maybe relevant to e nhancing the expression of IRS-1 mRNA and PPAR-γ mRNA