Oxysterols: modulators of cholesterol metabolism... [Physiol Rev. 2000] - PubMed - NCBI

Oxysterols: modulators of cholesterol metabolism and other processes.


derivatives of cholesterol (oxysterols) present a remarkably diverse
profile of biological activities, including effects on sphingolipid
metabolism, platelet aggregation, apoptosis, and protein prenylation.
The most notable oxysterol activities center around the regulation of
cholesterol homeostasis, which appears to be controlled in part by a
complex series of interactions of oxysterol ligands with various
receptors, such as the oxysterol binding protein, the cellular nucleic
acid binding protein, the sterol regulatory element binding protein, the
LXR nuclear orphan receptors, and the low-density lipoprotein receptor.
Identification of the endogenous oxysterol ligands and elucidation of
their enzymatic origins are topics of active investigation. Except for
24, 25-epoxysterols, most oxysterols arise from cholesterol by
autoxidation or by specific microsomal or mitochondrial oxidations,
usually involving cytochrome P-450 species. Oxysterols are variously
metabolized to esters, bile acids, steroid hormones, cholesterol, or
other sterols through pathways that may differ according to the type of
cell and mode of experimentation (in vitro, in vivo, cell culture).
Reliable measurements of oxysterol levels and activities are hampered by
low physiological concentrations (approximately 0.01-0.1 microM plasma)
relative to cholesterol (approximately 5,000 microM) and by the
susceptibility of cholesterol to autoxidation, which produces
artifactual oxysterols that may also have potent activities. Reports
describing the occurrence and levels of oxysterols in plasma,
low-density lipoproteins, various tissues, and food products include
many unrealistic data resulting from inattention to autoxidation and to
limitations of the analytical methodology. Because of the widespread
lack of appreciation for the technical difficulties involved in
oxysterol research, a rigorous evaluation of the chromatographic and
spectroscopic methods used in the isolation, characterization, and
quantitation of oxysterols has been included. This review comprises a
detailed and critical assessment of current knowledge regarding the
formation, occurrence, metabolism, regulatory properties, and other
activities of oxysterols in mammalian systems.

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From Wikipedia, the free encyclopedia
Oxysterols are oxidized derivatives of cholesterol, which may be important in many biological processes, including cholesterol homeostasis, sphingolipid metabolism, platelet aggregation, apoptosis, and protein prenylation,[1] though their roles are poorly understood. [2][3]

Frying foods in overused oil or smoking cigarettes can oxidize cholesterol, creating oxysterols.


  1. Jump up ^ Schroepfer, Gj, Jr (Jan 2000). "Oxysterols: modulators of cholesterol metabolism and other processes" (Free full text). Physiological reviews 80 (1): 361–554. ISSN 0031-9333. PMID 10617772.
  2. Jump up ^ Björkhem, I (Sep 2002). "Do oxysterols control cholesterol homeostasis?". The Journal of Clinical Investigation 110 (6): 725–30. doi:10.1172/JCI16388. PMC 151135. PMID 12235099.
  3. Jump up ^ Ingemar Björkhem; Ulf Diczfalusy (2002). "Oxysterols: Friends, Foes, or Just Fellow Passengers?". Arteriosclerosis, Thrombosis, and Vascular Biology 22 (5): 734–42. doi:10.1161/01.ATV.0000013312.32196.49. PMID 12006384.