Effects
of CLA on Hepatic Very Low Density Lipoprotein Metabolism
R. S. McLeod*, A. LeBlanc, M. Langille & D. Currie.
Dalhousie University, Halifax, NS.
We
have studied the effect of conjugated linoleic acid (CLA) isomers on very
low density lipoprotein (VLDL) metabolism in the rat hepatoma cell line,
McA-RH7777. Incubation of the hepatoma cells with 0.4 mM fatty acid, both
c-9, t-11 CLA and t-10, c-12 CLA stimulated an increase in rat hepatoma
cell triglyceride (TG) levels suggesting that both isoforms of CLA stimulate
TG synthesis and storage in the hepatocyte. Both isomers, like oleic acid,
stimulated the secretion of B48-VLDL. When provided as a minor component
of the total medium fatty acid (40 m) to cultures containing myristic
acid (at 0.36 mM), each CLA caused a shift in VLDL density, suggesting
they stimulate the assembly of mroe TG-rich VLDL. To test the potential
roles of CVA in lipoprotein metabolism in vivo, we supplemented the high
fat/cholesterol diets of Syrian Golden hamsters ( an established model
of diet-induced hyperlipoproteinemia) with 1% (w/w) c-9, t-11, or t-10,
c-12 CLA during the 10 week experiment. Plasma cholesterol was also unaffected
but plasma triglycerides were increased in the group fed t-10, c-12 CLA
(p<0.02 vs LA or c-9, t-11 CLA). These results suggest that isomeric
forms of CLA may have different effects on hepatic lipid and lipoprotein
metabolism.
This work is supported by research from the Dairy Farmers of Canada
