Esterification of exogenously derived free cholesterol by cultured fibroblasts.
The incorporation and esterification by cultured human fibroblasts of vesicle- or low density lipoprotein-derived free [3H]cholesterol was examined. The rate of the cellular uptake of free [3H]cholesterol from lipid vesicles was similar in both LDL-receptor positive lung fibroblasts and in LDL-receptor negative fibroblasts. When human LDL was used as the carrier of free [3H]cholesterol, however, the LDL-receptor positive lung fibroblasts incorporated significantly more [3H]cholesterol than did the LDL-receptor negative cells. The exchangeable free [3H]cholesterol was available for intracellular esterification. The formation of [3H]cholesteryl esters was markedly inhibited by lysosomotropic drugs, either indicating a partly lysosomal esterification reaction, or implying that free [3H]cholesterol moves through the lysosomal compartment on its way to intracellular esterification sites. Either way, the lysosomes appear to have a metabolic role in the metabolism of exchangeable free [3H]cholesterol.
D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism*; D002788:Cholesterol Esters / Q000378:metabolism*; D004951:Esterification; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D014316:Tritium
D002788:Cholesterol Esters; D011973:Receptors, LDL; D014316:Tritium; D002738:Chloroquine; D002784:Cholesterol