Perturbation of lipid metabolism by palmitic acid in Chinese hamster V79-R cells.

1. The addition of palmitic acid or myristic acid to a medium containing delipidated fetal bovine serum resulted in severe inhibition of V79-R cell growth. The degree of inhibition by palmitic acid was concentration dependent. Simultaneous addition of oleic acid protected the cells from the inhibition by palmitic acid. 2. In the presence of palmitic acid, total phospholipid and triacylglycerol per cell increased to 2- and 13-fold, respectively. 3. Palmitic acid caused an increase in the proportion of palmitic acid with concomitant decrease of oleic acid in phosphatidylcholine, phosphatidylethanolamine and triacylglycerol. 4. Palmitic acid inhibited the synthesis of phospholipid molecular species with two monoenoic fatty acids. However, membrane flow of phospholipids from endoplasmic reticulum to plasma membranes was preserved. 5. About 70% of the triacylglycerol molecular species were those containing three saturated or two saturated and one monoenoic fatty acids. 6. Electron microscopy revealed a large amount of triacylglycerol and fiber-like membrane structures in the cells supplemented with palmitic acid.