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标题：Palmitic acid acutely stimulates glucose uptake via activation of Akt and ERK1/2 in skeletal muscle cells
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作者：Jing Pu ; Gong Peng ; Linghai Li 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2011
卷号：52
期号：7
页码：1319-1327
DOI：10.1194/jlr.M011254
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Chronic exposure to saturated fatty acids can cause insulin resistance. However, the acute effects of fatty acids are not clear and need to be elucidated because plasma fatty acid concentrations fluctuate postprandially. Here, we present the acute effects of palmitate (PA) on skeletal muscle cells and their underlying molecular mechanisms. Immunofluorescence results showed that PA rapidly induced GLUT4 translocation and stimulated glucose uptake in rat skeletal muscle cell line L6. Phosphorylation of AMP-activated protein kinase (AMPK), Akt, and extracellular signal-related kinase1/2 (ERK1/2) was enhanced by PA in a time-dependent manner. Cell surface-bound PA was sufficient to stimulate Akt phosphorylation. The inhibitors of PI3 kinase (PI3K), AMPK, Akt, and ERK1/2 could decrease PA-induced glucose uptake, and PI3K inhibitor decreased AMPK, Akt, and ERK1/2 phosphorylation. Weakening AMPK activity reduced phosphorylation of Akt but not ERK1/2, and Akt inhibitor could not affect ERK1/2 activation either. Meanwhile, ERK1/2 inhibitors had no effect on Akt phosphorylation. Taken together, our data suggest that PA-mediated glucose uptake in skeletal muscle cells may be stimulated by the binding of PA to cell surface and followed by PI3K/AMPK/Akt and PI3K/ERK1/2 pathways independently.
关键词：fatty acid ; GLUT4 ; phosphorylation ; extracellular signal-related kinase ; PI3 kinase