The function of porcine PPARγ and dietary fish oil effect on the expression of lipid and glucose metabolism related genes.
Peroxisome-proliferator-activated receptor γ (PPARγ) plays a critical role in regulation of adipocyte differentiation and insulin sensitivity. To become functional, PPARγ must be activated by binding an appropriate ligand. Polyunsaturated fatty acids (PUFA) are potential ligands for PPARγ. The current experiment was designed to determine the potential for PUFA, particularly eicosapentaenoic acid and docosahexaenoic acid, to activate the function of porcine PPARγ in vivo. Transgenic mice, expressing porcine PPARγ in skeletal muscle were generated and fed with a high-saturated fat (beef tallow) or high-unsaturated fat (fish oil) diet for 4 months. When transgenic mice were fed a fish oil supplemented diet, the expression of adipogenic and glucose uptake genes was increased, leading to reduced plasma glucose concentration. The PPARγ transgene increased the expression of Glut4 in the muscle. This result suggests that there was increased glucose utilization and, therefore, a reduced blood glucose concentration in the transgenic mice. Also, the plasma adiponectin was elevated by fish oil treatment, suggesting a role of adiponectin in mediating the PUFA effect. These results suggest that PUFA may serve as a natural regulator of glucose uptake in vivo and these effects are mainly through PPARγ function.
Yu
Yu-Hsiang
YH
Department of Animal Science and Technology/Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan.
Wu
Shinn-Chih
SC
Cheng
Winston Teng-Kuei
WT
Mersmann
Harry J
HJ
Shen
Tang-Long
TL
Ding
Shih-Torng
ST
D052242:Adiponectin / Q000235:genetics / Q000378:metabolism; D000818:Animals; D004042:Dietary Fats, Unsaturated / Q000378:metabolism*; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D005395:Fish Oils / Q000378:metabolism*; D005786:Gene Expression Regulation; D005947:Glucose / Q000235:genetics* / Q000378:metabolism; D007333:Insulin Resistance; D050356:Lipid Metabolism / Q000235:genetics*; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018482:Muscle, Skeletal / Q000737:chemistry; D047495:PPAR gamma / Q000235:genetics / Q000378:metabolism*; D013552:Swine
D052242:Adiponectin; D004042:Dietary Fats, Unsaturated; D005395:Fish Oils; D047495:PPAR gamma; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D005947:Glucose