title: Scavenger lipoprotein receptors are more effective in ligand internalization than low density lipoprotein receptors in human monocyte-macrophages.
abstract: Human monocyte-macrophages in culture express specific receptors for low density lipoproteins (LDL receptor) and human acetylated LDL (AcLDL receptors or scavenger receptors). After 24 h in lipoprotein-deficient serum, the cells expressed 2-3 fold more AcLDL receptors than LDL receptors as measured by trypsin releasable radioactivity after exposure to 125I-LDL or 125I-AcLDL at 37 degrees C. The efficiency of intracellular ligand delivery by the two receptors was evaluated as an internalization index (defined as intracellular + degraded/bound ligand). This index was several fold greater for 125I-AcLDL than for 125I-LDL, in the same cells exposed to either ligand under identical conditions. These results suggest that the scavenger receptors recycle more rapidly than do LDL receptors.
mesh_terms: D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D006801:Humans; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011973:Receptors, LDL; D051116:Receptors, Scavenger; D013997:Time Factors
chemical_list: D015815:Cell Adhesion Molecules; D011956:Receptors, Cell Surface; D011973:Receptors, LDL; D051116:Receptors, Scavenger; D003513:Cycloheximide