Sterol 1101329 218124468 2008-06-09T07:34:32Z Littlealien182 3345501 Added {{[[Template:expand|expand]]}} tag to article. using [[WP:FRIENDLY|Friendly]] {{expand|date=June 2008}} [[Image:Sterol skeleton.png|right]] '''Sterols''', or '''steroid alcohols''' are a subgroup of [[steroid]]s with a [[hydroxyl group]] at the 3-position of the A-ring.<ref>{{cite journal |author=Fahy E, Subramaniam S, Brown HA, ''et al'' |title=A comprehensive classification system for lipids |journal=J. Lipid Res. |volume=46 |issue=5 |pages=839–61 |year=2005 |pmid=15722563 |url=http://www.jlr.org/cgi/content/full/46/5/839 |doi=10.1194/jlr.E400004-JLR200}}</ref> They are [[amphipathic lipids]] synthesized from [[acetyl-coenzyme A]] via the [[HMG-CoA reductase]] pathway. The overall molecule is quite flat. The hydroxyl group on the A ring is [[Chemical polarity|polar]]. The rest of the [[aliphatic]] chain is [[Chemical polarity|non-polar]]. Sterols of [[plant]]s are called ''[[phytosterol]]s'' and sterols of [[animal]]s are called ''zoosterols''. Important zoosterols are [[cholesterol]] and some [[steroid hormone]]s; notable phytosterols include [[campesterol]], [[sitosterol]], and [[stigmasterol]]. [[Ergosterol]] is a sterol present in the [[cell membrane]] of [[Fungus|fungi]], where it serves a role similar to cholesterol in animal cells. Sterols and related compounds play essential roles in the physiology of [[eukaryote|eukaryotic]] organisms. For example, cholesterol forms part of the cellular membrane in animals, where it affects the cell membrane's fluidity and serves as [[secondary messenger]] in developmental signaling. In humans and other animals, [[corticosteroids]], such as [[cortisol]] act as signalling compounds in cellular communication and general metabolism. Phytosterols may block cholesterol absorption sites in the human intestine thus helping to reduce cholesterol in humans. {{Fact|date=June 2008}} ==See also== *[[Cholesterol]] *[[Phytosterol]] *[[Ergosterol]] == References== {{reflist}} Molecular Biology of the Cell (Alberts et al., 2002) [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?highlight=cholesterol,bilayer&rid=mboc4.section.1864#1874] == External links== *[http://www.cyberlipid.org/sterols/ster0003.htm Sterols] Cyberlipid.org {{Membrane lipids}} {{Sterols}} [[Category:Sterols]] [[Category:Steroids]] {{biochem-stub}} [[de:Sterine]] [[es:esterol]] [[eo:Sterolo]] [[fr:Stérol]] [[it:Steroli]] [[he:סטרול]] [[ja:ステロール]] [[pl:Sterol]] [[pt:Esterol]] [[ro:Sterol]] [[th:สเตอรอล]] [[tr:Sterol]]