Effect of oleic, linoleic, gamma?linolenic and alpha?linolenic acids on VLDL?TG and cholesterol synthesis in rat primary cultured hepatocytes.
Effect of oleic, linoleic, gamma?linolenic and alpha?linolenic acids on VLDL?TG and cholesterol synthesis in rat primary cultured hepatocytes.
Year: 1994
Authors: Y Fujiyama-Fujiwara, O Igarashi.
Publication Name: Pathophys.
Publication Details: Volume 1; Page 143.
Abstract:
In order to better understand the role of polyunsaturated fatty acids in the regulation of lipid metabolism in hepatocytes, the effects of oleic acid (OL), LA, GLA and ALA on lipid synthesis and lipoprotein secretion were assessed in rats. The incorporation of [14C] glycerol into TG was increased in rat primary cultured hepatocytes by the addition of all fatty acids. GLA was elongated to DGLA, but was not metabolized to AA. ALA was not synthesized to other n?3 fatty acids but reduced the synthesis of AA. There were no fatty acid effects on total TG synthesis from [14C] glycerol or on the sum of incorporated TG from [14C] glycerol in the cells or in the medium. The authors indicated that these results suggest that n-3 PUFAs such as ALA and n-6 PUFAs regulate very low density lipoprotein (VLDL) synthesis. With the addition of LA, GLA or ALA, the radioactivity of TG in the medium, but not in the cells, was significantly lower. Total cholesterol synthesis from [14C] acetate was increased in a dose?dependent fashion with the addition of OL. LA, GLA and ALA decreased total cholesterol synthesis and secretion into the medium. VLDL?TG and cholesterol synthesis was reduced to a greater degree by GLA than by LA which may explain why GLA is more effective than LA at reducing serum cholesterol levels, a finding that has been reported by other researchers. The data reported suggest that PUFAs act as substrates for lipid esterification through acyl?CoA synthetase and also regulate de novo synthesis and/or the secretion of lipoproteins from hepatocytes.
