Lipid Metabolism in Cultured Cells. V. Comparative Lipid Nutrition in Serum and in Lipid-Free Chemically Defined Medium. ∗

Summary

Mammalian cells in tissue culture derive most of their lipid requirements from serum customarily used in growth medium. L-strain mouse fibroblasts were grown both on serum supplemented medium and on a recently developed chemically defined lipid-free medium (NCTC 109). Lipid composition of cells was essentially independent of growth medium used. When grown in synthetic medium, cell lipids were synthesized de novo from C¹⁴-acetate added to medium. In serum supplemented medium de novo synthesis from C ¹⁴-acetate was almost completely depressed. C¹⁴-labeled cell lipids were fractionated on silicic acid columns. Serum depressed acetate incorporation approximately equally in all lipid classes. It seems possible that this represents operation of feedback type mechanism for control of cellular lipid composition.