Effect of PPAR-α and -γ agonist on the expression of visfatin, adiponectin, and TNF-α in visceral fat of OLETF rats☆

Abstract A variety of adipocytokines and peptides secreted from adipocytes have been considered to play a crucial role in obesity, insulin resistance, and type 2 diabetes. Recently, visfatin, a new adipocytokine, known as a pre-B cell colony-enhancing factor, has been isolated from visceral fat deposits. It has been shown to activate insulin receptors in a manner different from insulin. To understand the role of adipocytokines in improving insulin sensitivity via activation of the nuclear receptor peroxisome proliferator-activated receptor-α (PPAR-α) and -γ (PPAR-γ), we examined the expression of visfatin, adiponectin, and TNF-α in visceral fat depots of Otsuka Long–Evans Tokushima fatty (OLETF) rats from early to advanced diabetic stage (from 28 to 40 weeks of age). Serum glucose and insulin concentrations significantly ( P P P P