Lipid Metabolism in Cultured Cells VII. Linoleic Acid Content of Cells Grown on Lipid-Free Synthetic Medium. ∗

Summary

The fatty acid composition of L-strain mouse fibroblasts growing both in serum and in lipid-free synthetic medium was measured. Linoleic acid comprised about 17% of the total fatty acids in cells grown on serum-supplemented medium and about 6% in cells grown for prolonged periods in lipid-free chemically defined medium. In contrast to other fatty acids however linoleic acid was not synthesized from C¹⁴-acetate added to the growth medium. The most probable explanation of these anomalous findings is that cells under deficiency conditions can conserve traces of linoleic acid which are present below detectable levels in the culture environment. No synthesis of positional iso-mers of linoleic acid similar to that which may occur in linoleic acid deficiency in vivo was observed.