Metabolism of CLA isomers, c9,t11- & t10,c12 in adipocyte cultures and their effect on delta-6 desaturase expression.

Abstract Text: Commercial conjugated linoleic acid (CLA) dietary supplements of contain equal mixtures of the C18:2 isomers, c9,t11-18:2 and t10,c12-18:2. CLA -c9t11 occurs naturally in meat and dairy products, whereas the t10,c12 CLA occurs mainly through chemical synthesis. Biological activity of these 2 isomers differ, c9,t11-18:2 has anti-inflammatory properties, while the t10,c12-18:2 inhibits lipid accumulation. CLA t10c12-18:2 and c9t11-18:2 were added to 3T3 adipocyte cultures to study their effect on gene transcription and identify their metabolites. In mature adipocytes, t10,c12-CLA decreased fatty acid synthase (FAS) and increased carnitine palmitoyltransferase 1 (CPT1) expression, which increased fatty acid oxidation. The t10,c12-18:2 was not readily elongated to C20 products but was delta-6 desaturated (FADs2) to C18:3–6t10c12. In contrast, the c9,t11-18:2 did not significantly alter gene expression but was significantly desaturated and elongated (Elov5) and to C20 and C22 metabolites, indicating potential eicosanoid production and reduced lipid accumulation.

Keywords: CLA, gene expression, adipocyte.