Alterations in CPT‐1 mRNA and fatty acid profile in hepatic cell lines in response to treatment with t 10, c 12‐ or c 9, t 11‐conjugated linoleic acid

Trans 10, cis 12‐conjugated linoleic acid ( t 10, c 12‐CLA) increases liver weights and hepatic lipids in mice. The purpose of this study was to determine the effects of CLA isomers ( t 10, c 12‐CLA or c 9, t 11‐CLA) and carnitine palmitoyl transferase‐1 (CPT‐1) inhibitors (etomoxir or hemipalmitoylcarnitinium) on CPT‐1 mRNA, fatty acid profile, and cholesterol synthesis in AML‐12 and HepG2 cells. t 10, c 12‐CLA was incorporated to a greater extent in both cell lines than c 9, t 11‐CLA. In addition, t 10, c 12‐CLA increased the free cholesterol content of AML‐12 and HepG2 cells four‐ and fivefold, respectively. Cells incubated with medium containing CPT‐1 inhibitors or t 10, c 12‐CLA had higher levels of mRNA for CPT‐1 in both cell lines, indicating an increased fatty acid oxidation in hepatic cell lines due to t 10, c 12‐CLA. Following treatment withdrawal, percentages of c 9, t 11‐CLA or t 10, c 12‐CLA remained elevated in cells initially treated with c 9, t 11‐CLA or t 10, c 12‐CLA, suggesting a potential for carryover effects of the CLA isomers. The results presented here demonstrate a potential role for t 10, c 12‐CLA in the modulation of hepatic fatty acid oxidation and cholesterol synthesis.