抄録
We investigated the metabolism of Phospholipid transported by Low Density Lipoprotein (LDL-PL) using Smooth Muscle Cell (SMC) compared with Cholesterol Ester transported by LDL (LDL-CE). LDL-PL was labeled with 1-linoleoyl-2-[14C] linoleoyl phosphatidylcholine and LDL-CE was labeled with cholesteryl-[14C]-oleate.
LDL linearly incorporated into SMC up to 18 hours and the amount of hydrolysis of LDL-PL and LDL-CE depended on incubation time. The LDL metabolism, which was measured as incorporation of radiolabeled FFA, showed almost the same as that of exogenous FFA added to the incubation medium.
Next, intercellular localization of radiolabeled lipids produced by the incubation of LDL-CE and LDL-PL was investigated. Most of radiolabeled PL or CE was observed in lysosomal fraction, when LDL-PL or LDL-CE was incubated, respectably. These results suggest that incorporated LDL was initially incorporated into lysosome and hydrolyzed.
It is well known that accumulated PL which was observed in atheromatous lesions was produced de novo synthesis in the cell. So, we investigated the effect of LDL on the regulation of PL metabolism in SMC. The incorporation into lipids from acetate in the presence of LDL was examined. Synthesis in SMC was not induced by the incorporation of LDL.
