Relationships between lymphocyte cholesterol homeostasis and LDL-cholesterol.
The homeostasis of cholesterol was studied in lymphocytes freshly isolated from the blood and cultured with or without low-density lipoprotein (LDL). The content of cholesterol decreased in the lymphocytes cultured without LDL, whereas LDL substituted for cellular cholesterol losses, in spite of almost suppressed LDL-receptor and lymphocyte cholesterol synthesis. Free cholesterol was taken up from LDL mainly via cholesterol exchange and, in contrast to esterified cellular cholesterol, rapidly excreted into the medium. In vitro stimulation of lymphocyte cholesterol synthesis was correlated to the ratio of esterified to free LDL-cholesterol in the blood from which the lymphocytes had been isolated. This result probably reflects the different rates of influx and efflux of esterified or free cholesterol between plasma lipoproteins and lymphocytes. These effects should be taken into account if LDL-cholesterol is determined in plasma for the evaluation of an individual's atherosclerotic risk.
D002478:Cells, Cultured; D002784:Cholesterol / Q000097:blood*; D002788:Cholesterol Esters / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood*; D006706:Homeostasis; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male
D002788:Cholesterol Esters; D008078:Cholesterol, LDL; D002784:Cholesterol