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The epidermal strata of the skin. 7-Dehydrocholesterol (7-DHC) is a zoosterol that functions in the serum as a cholesterol precursor, and is photochemically converted to vitamin D 3 in the skin, therefore functioning as provitamin-D 3. The presence of this compound in human skin enables humans to manufacture vitamin D 3 (cholecalciferol).
Vitamin D 3 (cholecalciferol) is produced industrially by exposing 7-dehydrocholesterol to UVB and UVC light, followed by purification. The 7-dehydrocholesterol is sourced as an extraction from lanolin, a waxy skin secretion in sheep's wool. [203] Vitamin D 2 (ergocalciferol) is produced in a similar way using ergosterol from yeast as a ...
Cholecalciferol, also known as vitamin D 3 or colecalciferol, is a type of vitamin D that is produced by the skin when exposed to UVB light; it is found in certain foods and can be taken as a dietary supplement. [3] Cholecalciferol is synthesised in the skin following sunlight exposure. [4]
Previtamin D 3 is an intermediate in the production of cholecalciferol (vitamin D 3). It is formed by the action of UV light, most specifically UVB light of wavelengths between 295 and 300 nm, acting on 7-dehydrocholesterol in the epidermal layers of the skin. [1] [2] [3] The B ring of the steroid nucleus structure is broken open, making a ...
cholecalciferol: fat fatty fish (mackerel, salmon, sardines), fish liver oils, eggs from hens fed vitamin D D 4: 22-dihydroergocalciferol: fat D 5: sitocalciferol: fat E: tocopherols, tocotrienols: fat 15 mg/15 mg deficiency is very rare; mild hemolytic anemia in newborn infants [20] possible increased incidence of congestive heart failure. [21 ...
Calcifediol binds in the blood to vitamin D-binding protein (also known as gc-globulin) and is the main circulating vitamin D metabolite. [4] [5] Calcifediol has an elimination half-life of around 15 to 30 days. [4] [9] Calcifediol is further hydroxylated at the 1-alpha-position in the kidneys to form 1,25-(OH) 2 D 3, calcitriol.
Calcitriol is a hormone and the active form of vitamin D, normally made in the kidney. [8] [9] [10] It is also known as 1,25-dihydroxycholecalciferol.It binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the expression of many genes. [11]
Ergosterol powder is an irritant to skin, eyes, and the respiratory tract. Ingestion of large amounts can cause hypercalcemia , which (if prolonged) can lead to calcium salt deposits in the soft tissues and kidneys.