Fig. 1.

Peroxisome proliferator-activated receptor-α (PPARα) influences expression of sirtuin 1 (SIRT1). A: RT-quantitative PCR (qPCR) analysis of hepatic Sirt1 expression in wild-type (WT) and Ppara^−/− mice treated for 5 days with fenofibrate (FF) or WY-14643 (WY). Expression of the known PPARα target gene Acox1 was included as a positive control. Values were normalized to β-actin and expressed as fold change over the control WT. Significant changes in expression between treated and control mice of the same genotype are indicated (*P < 0.05). Significant differences in Sirt1 expression between WT and Ppara^−/− mice are indicated (†P < 0.05). B: Western blot analysis of whole cell extracts from livers of WT mice treated with FF or WY for 5 days. Extracts from fasted mice and Sirt1^ΔLiv mice were used as antibody controls. Densitometry values for each SIRT1 band were normalized to β-actin expression for each lane and presented as relative density. NS, not significant.