Berberine regulates peroxisome proliferator-activated receptors and positive transcription elongation factor b expression in diabetic adipocytes

Berberine has hypoglycemic and hypolipidemic effects on diabetic rats This study investigated the relationship between hypoglycemic and hypolipidemic effects of berberine and peroxisome proliferator-activated receptors (PPARs) and positive transcription elongation factor b (P-TEFb) (including cyclin-dependent kinase 9 (CDK9) and cyclin T1) in white adipose tissue of diabetic rats and RNA interference-treated 3T3-L1 cells Berberine promoted differentiation and inhibited lipid accumulation of 3T3-L1 cells further decreased PPAR alpha/delta/gamma CDK9 and cyclin T1 mRNA and protein expression and decreased tumor necrosis factor a content in supernatants of both control and RNA interference-treated 3T3 L1 cells After a 16-week induction with 35 mg/kg streptozotocin (i p) and high-carbohydrate/high-fat diet diabetic rats were treated with 75 150 and 300 mg/kg berberine and 100 mg/kg fenofibrate or 4 mg/kg rosiglitazone for another 16 weeks Berberine decreased white adipose tissue to body weight ratio and adipocyte size and increased adipocyte number Berberine upregulated PPAR alpha/delta/gamma CDK9 and cyclin T1 mRNA and protein expression in adipose tissue decreased tumor necrosis factor alpha and free fatty acid content and increased lipoprotein lipase activity in serum and adipose tissue Berberine modulated metabolic related PPARs expression and differentiation related P-TEFb expression in adipocytes which are associated with its hypoglycemic and hypolipidemic effects (C) 2010 Elsevier B V All rights reserved