| Abstrakt: |
Conjugated linoleic acids (CLA) are known to reduce body fat and plasma lipids in animal models. This study examined the short-term effects of 2 biologically active isomers of CLA (cis-9, trans-11 and trans-10, cis-12) on lipid-metabolizing genes and high-density lipoprotein (HDL) cholesterol production in cultured HepG2 cells. Steady-state levels of acyl CoA oxidase (ACO); 3-hydroxy, 3-methylglutaryl CoA reductase (HMG-R); and apolipoprotein A-I (Apo A-I) mRNA were examined after 24-hour incubation in the absence (control) or presence of 100 µm each of linoleic acid (LA), cis-9, trans-11 CLA or trans-10, cis-12 CLA. Concentrations of ACO and HMG-R mRNA transcripts were increased in HepG2 cells treated with trans-10, cis-12 CLA. Incubation with MK886, a specific PPARα inhibitor, had minimal effect on basal or CLA-induced gene expression in HepG2 cells. The cis-9, trans-11, but not trans-10, cis-12, CLA decreased HDL cholesterol concentration in cell-conditioned media. There was no apparent relationship between Apo A-I and HDL cholesterol responses to fatty acids. Results indicate that CLA may control peroxisomal oxidation of fatty acids through up-regulation of hepatic ACO gene expression. The physiological relevance of CLA effect on HMG-R mRNA content in the liver is yet to be determined. [ABSTRACT FROM AUTHOR] |
