Exercise improved rat metabolism by raising PPAR-α

Based on the importance of exercise and crucial role of liver in metabolism, the aim of this study was to determine whether the expression of peroxisome proliferator-activated receptor (PPAR)-α, γ and adiponectin receptor 2 in OLETF rat liver were altered in conjunction with improved metabolism with exercise training. OLETF rats were randomly assigned to 2 groups: sedentary control group (n=26), and long-term exercise-trained group (n=26). Full data were available on 32 OLETF rats (16 for each group). Adiponectin, glucose, insulin, triglyceride and cholesterol were assessed. Livers were taken to determine the expression of PPAR-α, γ and adiponectin receptor 2. Compared with sedentary control group, fasting glucose (9.38 ± 2.99 mmol/L vs. 7.32 ± 1.76 mmol/L, P<0.05), triglyceride (1.73 ± 0.34 mmol/L vs. 0.89 ± 0.12 mmol/L, P<0.05) and cholesterol (4.41 ± 0.75 mmol/L vs. 2.13 ± 0.32 mmol/L, P<0.05) were substantially reduced after exercise, which significantly correlated with increased PPAR-α (P<0.05) in liver. The expression of PPAR-α upstream and target genes, including hepatocyte nuclear factor-4 (HNF4), carnitine palmitoyl transferase 1 (CPT-1), catalase (CAT) and ATPbinding cassette transporter A1 (ABCA1) also increased significantly. Therefore, our findings suggest that increased PPAR-α expression in OLETF rats liver is a contributory factor to the exercise-related improvements in whole-body metabolism.