Trans-10, cis-12 conjugated linoleic acid increases fatty acid oxidation in 3T3-L1 preadipocytes.
The purpose of this study was to examine the effect of 0-50 micromol/L trans-10, cis-12 conjugated linoleic acid (CLA) and cis-9, trans-11 CLA isomers on lipid and glucose metabolism in cultures of differentiating 3T3-L1 preadipocytes. Specifically, we investigated the effects of 6 d of CLA treatment on the following: 1) (14)C-glucose and (14)C-oleic acid incorporation and esterification into lipid; 2) (14)C-glucose and (14)C-fatty acid oxidation; and 3) basal and isoproterenol-stimulated lipolysis. Trans-10, cis-12 CLA supplementation (25 and 50 micromol/L) increased both (14)C-glucose and (14)C-oleic acid incorporation into the cellular lipid fraction, which was primarily triglyceride (TG), compared with bovine serum albumin (BSA) controls. Although glucose oxidation ((14)C-glucose to (14)C-CO(2)) was unaffected by CLA supplementation, oleic acid oxidation ((14)C-oleic acid to (14)C-CO(2)) was increased by approximately 55% in the presence of 50 micromol/L trans-10, cis-12 CLA compared with BSA controls. In contrast, 50 micromol/L linoleic acid (LA) and cis-9, trans-11 CLA-treated cultures had approximately 50% lower CO(2) production from (14)C-oleic acid compared with control cultures after 6 d of fatty acid exposure. Finally, 50 micromol/L trans-10, cis-12 CLA modestly increased basal, but not isoproterenol-stimulated lipolysis compared with control cultures. Thus, the TG-lowering actions of trans-10, cis-12 CLA in cultures of 3T3-L1 preadipocytes may be via increased fatty acid oxidation, which exceeded its stimulatory effects on glucose and oleic acid incorporation into lipid.
Evans
M
M
Graduate Program in Nutrition, University of North Carolina at Greensboro, Greensboro, NC 27402, USA.
Lin
X
X
Odle
J
J
McIntosh
M
M
D016475:3T3 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002250:Carbon Radioisotopes; D002851:Chromatography, High Pressure Liquid; D004951:Esterification; D005227:Fatty Acids / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D019787:Linoleic Acid / Q000737:chemistry / Q000494:pharmacology*; D050356:Lipid Metabolism; D051379:Mice; D019301:Oleic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D013234:Stem Cells / Q000187:drug effects* / Q000378:metabolism; D013237:Stereoisomerism
D002250:Carbon Radioisotopes; D005227:Fatty Acids; D019301:Oleic Acid; D019787:Linoleic Acid; D005947:Glucose