Fig. 3.
Lipid composition and localization of cellular and exogenous lipid after exchange at 37 °C. (A) Percentage residual endogenous 3H labeled lipids in A549 cells after 1 h exchange with 1.5 mM bSM and 40 mM MαCD. (Radioactivity after exchange/radioactivity before exchange) × 100% was calculated for each lipid as shown, with values before exchange normalized to 100% for each lipid. Average values of three experiments and SDs are shown. (B) TLC of A549 lipids after 1 h exchange. Exogenous lipids were loaded onto 40 mM MαCD. (Lane 1) Control samples with no MαCD or exogenous lipids. (Lane 2) Treatment with 1.5 mM exogenous bSM but no MαCD. (Lane 3) Exchange with 1.5 mM exogenous bSM and MαCD. (Lane 4) Exchange with 3 mM exogenous POPC and MαCD. The low mobility section of a TLC plate onto which 1/10 of total sample was chromatographed is shown. Notice that SM runs as multiple bands.