title: Low density lipoprotein causes general cellular activation with increased phosphatidylinositol turnover and lipoprotein catabolism.
abstract: Low density lipoprotein (LDL), at concentrations high enough for receptor binding but not high enough to saturate the receptor, induces activation of phosphatidylinositol (PtdIns) turnover in a variety of cell types with various biological functions. Using both biochemical and electron microscopic studies, we have shown that blood platelets take up and degrade LDL in a manner reminiscent of phagocytic cell types. The activation of both PtdIns turnover and LDL metabolism is inhibited by high density lipoprotein. Thus, LDL at hormonal concentrations causes general cellular activation. Since all cell types studied responded to LDL with increased PtdIns turnover and uptake of LDL cholesterol, the PtdIns cycle may also be involved in the cellular regulation of LDL cholesterol metabolism.
authors.affiliation: Department of Medicine, University of Basel, Switzerland.
authors.forename: L H
authors.initials: LH
authors.lastname: Block
authors.forename: M
authors.initials: M
authors.lastname: Knorr
authors.forename: E
authors.initials: E
authors.lastname: Vogt
authors.forename: R
authors.initials: R
authors.lastname: Locher
authors.forename: W
authors.initials: W
authors.lastname: Vetter
authors.forename: P
authors.initials: P
authors.lastname: Groscurth
authors.forename: B Y
authors.initials: BY
authors.lastname: Qiao
authors.forename: D
authors.initials: D
authors.lastname: Pometta
authors.forename: R
authors.initials: R
authors.lastname: James
authors.forename: M
authors.initials: M
authors.lastname: Regenass
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D009928:Organ Specificity; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011973:Receptors, LDL / Q000378:metabolism
chemical_list: D007295:Inositol Phosphates; D008077:Lipoproteins, LDL; D010716:Phosphatidylinositols; D011973:Receptors, LDL