The objective of this study was to investigate whether the n-3 polyunsaturated fatty acids (PUFA) docosahexaenoic (DHA) and eicosapentaenoic (EPA) can directly regulate glucose and fat metabolism in skeletal muscle besides exerting anti-inflammatory effects. To accomplish this, L6 skeletal muscle cells were treated with 50μM of either DHA or EPA for 1, 3, and 5 days. Here, we report that basal and insulin-stimulated rates of glucose uptake, glycogen synthesis, protein kinase B (AKT), and glycogen synthase kinase 3 (GSK3) phosphorylation were not affected by DHA or EPA. However, glucose and palmitate oxidation were consistently elevated by DHA treatment, whereas EPA only increased this variable transiently. Similarly, only DHA caused significant and sustained increases in AMP-activated protein kinase (AMPK) phosphorylation and protein levels of carnitine-palmitoyl transferase 1b (CPT1b) and peroxisome proliferator-activated receptor gamma coactivator 1α (PGC-1α) in skeletal muscle cells. DHA also caused a larger anti-inflammatory effect than EPA in these cells. In conclusion, besides exerting anti-inflammatory effects, DHA and EPA directly regulated glucose and fat metabolism in skeletal muscle cells, although DHA was more effective in doing so than EPA. Thus, by directly enhancing glucose and fat oxidation, DHA may increase glucose disposal and reduce intramyocellular lipid accumulation.

中文翻译：

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二十二碳六烯酸和二十碳五烯酸脂肪酸差异调节L6大鼠骨骼肌细胞中的葡萄糖和脂肪酸代谢。

这项研究的目的是研究n-3多不饱和脂肪酸（PUFA）二十二碳六烯酸（DHA）和二十碳五烯酸（EPA）是否除了发挥抗炎作用外，还可以直接调节骨骼肌中的葡萄糖和脂肪代谢。为此，用50μMDHA或EPA处理L6骨骼肌细胞1天，3天和5天。在这里，我们报道基础和胰岛素刺激的葡萄糖摄取率，糖原合成，蛋白激酶B（AKT）和糖原合酶激酶3（GSK3）磷酸化不受DHA或EPA影响。然而，葡萄糖和棕榈酸酯的氧化一直通过DHA处理而升高，而EPA仅暂时增加了该变量。同样，只有DHA引起骨骼肌细胞中AMP激活的蛋白激酶（AMPK）磷酸化和肉碱-棕榈酰转移酶1b（CPT1b）和过氧化物酶体增殖物激活的受体γ辅激活子1α（PGC-1α）的蛋白水平显着且持续的增加。在这些细胞中，DHA还比EPA引起更大的抗炎作用。总之，除了DHA和EPA发挥抗炎作用外，它还直接调节骨骼肌细胞中的葡萄糖和脂肪代谢，尽管DHA比EPA更有效。因此，通过直接增强葡萄糖和脂肪的氧化，DHA可以增加葡萄糖的处置并减少肌内脂质的积累。在这些细胞中，DHA还比EPA引起更大的抗炎作用。总之，除了DHA和EPA发挥抗炎作用外，它还直接调节骨骼肌细胞中的葡萄糖和脂肪代谢，尽管DHA比EPA更有效。因此，通过直接增强葡萄糖和脂肪的氧化，DHA可以增加葡萄糖的处置并减少肌内脂质的积累。在这些细胞中，DHA还比EPA引起更大的抗炎作用。总之，除了DHA和EPA发挥抗炎作用外，它还直接调节骨骼肌细胞中的葡萄糖和脂肪代谢，尽管DHA比EPA更有效。因此，通过直接增强葡萄糖和脂肪的氧化，DHA可以增加葡萄糖的处置并减少肌内脂质的积累。