Abstract
Human low density lipoprotein (LDL) was modified by exposure to cultured human endothelial cells. The endothelial cell modified LDL (EC-LDL) and control LDL (con LDL) labelled with 125I-tyramincellobiose (125I-TC) were injected into rats. Since 125I-TC is trapped in lysosomes the contribution of various organs to the catabolism of EC-LDL and con LDL could be studied. First, EC-LDL was cleared from plasma several times faster than con LDL. Then, the liver was found to be the major organ for catabolism of EC-LDL. Con LDL was distributed more evenly among the spleen, liver and adrenals as the main organs. In the liver the endothelial cells were most effective in degrading EC-LDL whereas con LDL was distributed approximately evenly between the Kupffer, endothelial and parenchymal cells. Thus, the liver endothelial cells seem to be a major pathway for catabolism of modified LDL.