Kinase experiment:

cDNA encoding amino acids 174-475 of PPARγ1 is amplified via polymerase chain reaction and inserted into bacterial expression vector pGEX-2T. GST-PPARγ LBD is expressed in BL21(DE3)plysS cells and extracts. For saturation binding analysis, bacterial extracts (100 μg of protein) are incubated at 4℃ for 3 h in buffer containing 10 mM Tris (pH 8.0), 50 mM KCl, 10 mM dithiothreitol with [3H]-BRL49653 (specific activity, 40 Ci/mmol) in the presence or absence of unlabeled Rosiglitazone. Bound is separated from free radioactivity by elution through 1-mL Sephadex G-25 desalting columns. Bound radioactivity eluted in the column void volume and is quantitated by liquid scintillation counting[1].

Cell experiment:

C3H10T1/2 cells are grown in a 24-well plate in DME medium supplemented with 10% fetal calf serum. Medium and compound (Rosiglitazone) are exchanged every 3 days. Cells are stained at day 7 with Oil Red O and photographed[1].

Animal experiment:

Rats are intravenously injected with 38 mg/kg streptozotocin and after 48 h, diabetes is identified by urinary glucosuria and then random blood sugar is measured and this day is regarded as day 0. Animals with a serum glucose level of 220-300 mg/dL are selected to be used in this study. Rats are randomly separated into five groups for daily drug administration for 8 weeks: group 1: control nondiabetic rats given a vehicle only (0.5 mL/kg of 0.5% carboxy methyl celleluse orally), group 2: control diabetic rats given a vehicle, group 3: diabetic rats receiving Rosiglitazone (5 mg/kg orally), group 4: diabetic rats receiving losartan (2 mg/kg, orally), and group 5: diabetic rats receiving both Rosiglitazone and losartan[2].

Rosiglitazone maleate is the maleic acid salt form of rosiglitazone, a potent insulin sensitizer, which is used for the treatment of diabetes. Rosiglitazone belongs to a group of compounds, thiazolidinediones (TZDs), which selectively ligate the nuclear transcription factor peroxisome-proliferator-activated receptor-γ (PPARγ). As a TZD, rosiglitazone improves the sensitivity of end organs to insulin through PPARγ activation which poteniates them to lower concentrations of blood glucose. Despite of its beneficial effects of targeting insulin resistance, recent studies has shown that rosiglitazone is associated with several moderate to severe adverse effects, including hemodilution, anemia, weight gain, and edema as well as increased risk for heart failure and myocardial ischemic events.

Reference

[1].Andreas Pfutzner, Birgit Wilhelm, and Thomas Forst. Rosiglitazone and glimeperide: review of clinical results supporting a fixed dose conbination. Vascular Health and Risk Management 2007: 3(2) 211-220
[2].Adie Vilioen and Alan Sinclair. Safety and efficacy of rosiglitazone in the elderly diabetic patient. Vascular Health and Risk Management 2009:5 389-395