EFFECT OF TRANS10, CIS12-CONJUGATED LINOLEIC ACID ON GLUCOSE CONSUMPTION OF INSULIN RESISTANCE CHANG LIVER CELLS

Abstract

ABSTRACT The effect of conjugated linoleic acid (CLA) on insulin resistance (IR) was isomer specific. In the present study, we induced IR Chang liver cells by incubating cells with 100 nmol/L insulin for 24 h. Then the effect of trans10, cis12-conjugated linoleic acid (t10, c12-CLA) and cis9, trans11-conjugated linoleic acid (c9, t11-CLA) on IR cells were studied. 1 µmol/L, 2 µmol/L, 5 µmol/L and 10 µmol/L t10, c12-CLA, but not c9, t11-CLA were found to enhance glucose consumption of IR cells in a dose-dependent way. 2 µmol/L t10, c12-CLA for 12 h incubation significantly improved glucose consumption of IR cells and increased phospho-protein kinase B (p-PKB/p-Akt) protein level. The enhancement of glucose consumption of IR cells by t10, c12-CLA and the level of p-Akt was strongly inhibited by phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, indicating that PI3K/Akt insulin signaling pathway may be involved in the beneficial effect of t10, c12-CLA on alleviating IR. PRACTICAL APPLICATION The intake of dairy foods has been shown to be relevant with type 2 diabetes in various conditions. A potential group of biologically active compounds that attracted lots of attention these years to explain this effect might be CLA. However, the potential effect of CLA on diabetes is isomer-specific, thus, the study performed on pure CLA isomer is important to make the issue clearly. In the current study, we focused on the effect of pure t10, c12-CLA and c9, t11-CLA on IR, key characteristics of type 2 diabetes. The results show that t10, c12-CLA, rather than c9, t11-CLA improved the glucose uptake and utilization, suggesting a beneficial effect of t10, c12-CLA on alleviating type 2 diabetes. This conclusion may be of help in the research and development of functional food and pharmaceuticals rich in t10, c12-CLA for the therapy of IR and type 2 diabetes.