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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).
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]
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 ...
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 ...
Calcifediol is the precursor for calcitriol, the active form of vitamin D. [3] [4] It is synthesized in the liver, by hydroxylation of cholecalciferol (vitamin D 3) at the 25-position. [3] This enzymatic 25-hydroxylase reaction is mostly due to the actions of CYP2R1 , present in microsomes , although other enzymes such as mitochondrial CYP27A1 ...
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 ...
Mapping of several bone diseases onto levels of vitamin D (calcidiol) in the blood [6] Normal bone vs. osteoporosis. Vitamin D deficiency is typically diagnosed by measuring the concentration of the 25-hydroxyvitamin D in the blood, which is the most accurate measure of stores of vitamin D in the body.
Cholecalciferol, an example of a 9,10-secosteroid. IUPAC-approved carbon numbering and ring labeling is shown in the picture. Since secosteroids are derived from steroids, they retain the same labeling system as steroids. [1]: §3S-8 The parent steroid skeleton. The B-ring of the parent steroid is broken between C9 and C10 to yield D vitamins.