[Nonreceptor interaction of low-density lipoproteins with human fibroblasts]

An analysis was made of catabolism of low density lipids (LDL) labeled in the protein or lipid moieties with cultivated human fibroblasts under inhibition of receptor-mediated endocytosis of LDL. The results have shown that under these conditions, only part of LDL uptaken by the cells are catabolized in the cells for 24 h. A considerable part account for a slow-metabolized intracellular pool. LDL of the latter may leave the cells by exocytosis (regurgitation), appearing in the culture medium. On the whole, the data obtained agree with the basic regularities of LDL transport in the cell within the structure of uncoated vesicles.