Radioactive lipids distributions within gradient fractions. TLC separation of radioactive total lipid extracts obtained from sucrose gradient fractions 4, 5, 6, 10, and 11 prepared from normal (A) and NPA (B) fibroblasts. One thousand dpm were applied on a 4 mm line for each sample. TLC was run in CHCl3/CH3OH/0.2% aqueous CaCl2, 50:40:8 by vol. Digital autoradiography was performed with a Biospace β-imager instrument for 48 h.