cis-9,trans-11-Conjugated linoleic acid activates AMP-activated protein kinase in attenuation of insulin resistance in C2C12 myotubes.
Obesity is a key risk factor in the development of insulin resistance (IR). This study is to investigate the IR attenuating effect and the molecular mechanism of cis-9,trans-11-conjugated linoleic acid (c9,t11-CLA). This study was performed with a palmitate-induced IR model using C(2)C(12) myotubes and showed that c9,t11-CLA increased insulin-stimulated and basal (non-insulin-stimulated) glucose uptake of IR myotubes. c9,t11-CLA also up-regulated the levels of phosphorglycogen synthase, phosphoracetyl CoA carboxylase, and carnitine palmitoyltransferase-1 while down-regulating the level of pyruvate dehydrogenase kinase 4 under insulin-stimulated and basal conditions. However, c9,t11-CLA did not affect protein kinase B/Akt (Akt). These results suggested that c9,t11-CLA induced an insulin-independent enhancement of glucose and fatty acid metabolism. Furthermore, there was a dose- and time-dependent increase in the expression of phosphor-AMP-activated protein kinase (AMPK), whereas LKB1, the upstream kinase of AMPK, was unchanged. Collectively, c9,t11-CLA attenuated palmitate-induced IR by increasing the consumption of glucose and fatty acid, the mechanism involving the direct activation of AMPK.
Qin
Hong
H
Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin 150081, People's Republic of China.
Liu
Ying
Y
Lu
Na
N
Li
Ying
Y
Sun
Chang-Hao
CH
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation / Q000187:drug effects; D005227:Fatty Acids / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D007333:Insulin Resistance; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D019308:Palmitic Acid / Q000494:pharmacology
D005227:Fatty Acids; D044243:Linoleic Acids, Conjugated; C503589:cis-9, trans-11-conjugated linoleic acid; D019308:Palmitic Acid; D055372:AMP-Activated Protein Kinases; D005947:Glucose