Adiponectin receptor gene expression in human skeletal muscle cells is not regulated by fibrates and thiazolidinediones.

Abstract

Thiazolidinediones as PPARgamma agonists and fibrates as PPARalpha agonists improve insulin sensitivity in insulin-responsive tissues. Recent data show an induction of adiponectin receptor 2 (AdipoR2) by PPARalpha and PPARgamma agonists in human macrophages. In this study, we examined the effects of thiazolidinediones and fibrates on the expression of adiponectin receptors in human skeletal muscle cells, an important cell type in the context of insulin resistance. In vitro differentiated human myotubes treated with troglitazone or rosiglitazone (20 h) showed no significant changes in AdipoR1 and AdipoR2 mRNA expression. PPARgamma activation was controlled by determination of PPARgamma mRNA induction. Likewise, differentiated myotubes treated with Wy-14,643 or fenofibrate (20 h) revealed no significant regulation of AdipoR1 and AdipoR2 mRNA. PPARalpha activation was assessed by measuring PDHK4 mRNA expression. Induction of AdipoR gene expression in human skeletal muscle cells is not involved in the insulin-sensitizing effects of thiazolidinediones or fibrates.