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.
Department of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, 157 Baojian Road, Nangang District, Harbin 150081, People's Republic of China.
Hong
H
Qin
Ying
Y
Liu
Na
N
Lu
Ying
Y
Li
Chang-Hao
CH
Sun
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