Calcifediol
From Wikipedia, the free encyclopedia
| Calcifediol | |
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| IUPAC name |
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| Other names | 25-Hydroxyvitamin D3 25-Hydroxycholecalciferol Calcifediol |
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| CAS number | [] |
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| Properties | |
| Molecular formula | C27H44O2 |
| Molar mass | 400.64 g/mol |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references |
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Calcifediol (INN), also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D (abbreviated 25(OH)D), is a prehormone which is produced by hydroxylation of vitamin D3 (cholecalciferol) in the liver. Calcidiol is then converted in the kidneys (by the enzyme 25(OH)D-1α-hydroxylase) into calcitriol (1,25-(OH)2D3), a secosteroid hormone that is the active form of vitamin D. It can also be converted into 24-hydroxycalcidiol in the kidneys via 24-hydroxylation.[1][2]
[edit] Clinical significance
In medicine, blood concentration of calcidiol is considered the best (and most sensitive) indicator of vitamin D status.[3] Increasing calcidiol levels are associated with increasing fractional absorption of calcium from the gut up to levels of 80 nmol/L (32 ng/mL).[citation needed] Urinary calcium excretion balances intestinal calcium absorption and does not increase with calcidiol levels up to ~400 nmol/L (160 ng/mL).[4]
The normal range varies widely depending on several factors, including age and geographic location. A broad reference range of 20–150 nmol/L has been suggested,[5] while several studies have defined levels below 80 nmol/L as indicative of vitamin D deficiency.[6]
[edit] References
- ^ Bender, David A.; Mayes, Peter A (2006). "Micronutrients: Vitamins & Minerals". in Victor W. Rodwell; Murray, Robert F.; Harper, Harold W.; Granner, Darryl K.; Mayes, Peter A.. Harper's Illustrated Biochemistry. New York: Lange/McGraw-Hill. pp. 492–3. ISBN 0-07-146197-3. http://books.google.com.br/books?id=QrJCZ1v5T6AC. Retrieved December 10, 2008 through Google Book Search.
- ^ Institute of Medicine (1997). "Vitamin D". Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. Washington, D.C: National Academy Press. pp. 254. ISBN 0-309-06403-1. http://www.nap.edu/openbook.php?record_id=5776&page=250.
- ^ Institute of Medicine (1997), p. 259
- ^ Kimball et al. (2004). "Safety of vitamin D3 in adults with multiple sclerosis". J Clin Endocrinol Metab. PMID 17823429.
- ^ Bender, David A. (2003). "Vitamin D". Nutritional biochemistry of the vitamins. Cambridge: Cambridge University Press. ISBN 0-521-80388-8. http://books.google.com.br/books?id=pxEJNs0IUo4C. Retrieved December 10, 2008 through Google Book Search.
- ^ Hollis BW (February 2005). "Circulating 25-hydroxyvitamin D levels indicative of vitamin D sufficiency: implications for establishing a new effective dietary intake recommendation for vitamin D". J Nutr 135 (2): 317–22. PMID 15671234. http://jn.nutrition.org/cgi/pmidlookup?view=long&pmid=15671234.
[edit] External links
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