7-Dehydrocholesterol
7-Dehydrocholesterol is a zymosterol that is an intermediate in the biosynthesis of cholesterol. It is a precursor to vitamin D3 and is converted to this vitamin when skin is exposed to sunlight.
Structure and properties[edit | edit source]
7-Dehydrocholesterol is a sterol. It is similar in structure to cholesterol, but it has a double bond between the seventh and eighth carbon atoms in the B ring of the steroid structure. This double bond is what gives 7-dehydrocholesterol its name.
Biosynthesis[edit | edit source]
7-Dehydrocholesterol is synthesized from lanosterol in a series of reactions that involve the removal of three methyl groups, the reduction of a double bond, and the introduction of a double bond. The enzyme that introduces the double bond to form 7-dehydrocholesterol is 7-dehydrocholesterol reductase.
Role in vitamin D synthesis[edit | edit source]
When skin is exposed to ultraviolet B (UVB) radiation from the sun, 7-dehydrocholesterol in the skin is converted to previtamin D3. This is then converted to vitamin D3 (cholecalciferol) in a heat-dependent process. Vitamin D3 can be further metabolized to form the active form of vitamin D, calcitriol.
Clinical significance[edit | edit source]
Mutations in the gene that encodes 7-dehydrocholesterol reductase can lead to Smith-Lemli-Opitz syndrome, a genetic disorder characterized by intellectual disability and physical abnormalities. This is because these mutations result in a decrease in the production of cholesterol and an increase in the levels of 7-dehydrocholesterol.
See also[edit | edit source]
7-Dehydrocholesterol Resources | ||
---|---|---|
|
|
Translate to: East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
Urdu,
বাংলা,
తెలుగు,
தமிழ்,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
European
español,
Deutsch,
français,
русский,
português do Brasil,
Italian,
polski
Navigation: Wellness - Encyclopedia - Health topics - Disease Index - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro) available.
Advertise on WikiMD
WikiMD is not a substitute for professional medical advice. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD