Department of Animal Science and Technology/Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan.
J Nutr Biochem. 2011 Feb;22(2):179-86. doi: 10.1016/j.jnutbio.2010.01.006. Epub 2010 Oct 20.
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.
过氧化物酶体增殖物激活受体 γ（PPARγ）在调节脂肪细胞分化和胰岛素敏感性方面起着关键作用。为了发挥功能，PPARγ 必须通过与适当的配体结合来激活。多不饱和脂肪酸（PUFA）是 PPARγ 的潜在配体。本实验旨在确定多不饱和脂肪酸（特别是二十碳五烯酸和二十二碳六烯酸）在体内激活猪 PPARγ 功能的潜力。生成了在骨骼肌中表达猪 PPARγ 的转基因小鼠，并在 4 个月内用高饱和脂肪（牛脂）或高不饱和脂肪（鱼油）饮食喂养。当转基因小鼠喂食富含鱼油的饮食时，脂肪生成和葡萄糖摄取基因的表达增加，导致血浆葡萄糖浓度降低。PPARγ 转基因增加了肌肉中 Glut4 的表达。这一结果表明，转基因小鼠的葡萄糖利用率增加，因此血液葡萄糖浓度降低。此外，鱼油处理还可提高血浆脂联素水平，表明脂联素在介导 PUFA 作用中起作用。这些结果表明，PUFA 可能作为体内葡萄糖摄取的天然调节剂，这些作用主要通过 PPARγ 功能实现。
