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Unlike the other twelve vitamins, vitamin D is only conditionally essential - in a preindustrial society people had adequate exposure to sunlight and the vitamin was a hormone, as the primary natural source of vitamin D was the synthesis of cholecalciferol in the lower layers of the skin's epidermis, triggered by a photochemical reaction with ...
The Institute of Medicine in 2010 recommended a maximum uptake of vitamin D of 4000 IU/d, finding that the dose for lowest observed adverse effect level is 40,000 IU daily for at least 12 weeks, [25] and that there was a single case of toxicity above 10 000 IU after more than seven years of daily intake; this case of toxicity occurred in ...
Ergocalciferol, also known as vitamin D 2 and nonspecifically calciferol, is a type of vitamin D found in food. It is used as a dietary supplement [3] to prevent and treat vitamin D deficiency [4] due to poor absorption by the intestines or liver disease. [5]
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.
The natural, active form of vitamin D is calcitriol (1,25-dihydroxycholecalciferol). This molecule and other naturally occurring forms of vitamin D, including its precursors and metabolites, have been modified to synthesize pharmaceuticals with potentially greater, or selective, therapeutic actions. [1] [2] [3] [4]
Ergosterol (ergosta-5,7,22-trien-3β-ol) is a sterol found in fungi, and named after ergot, the common name of members of the fungal genus Claviceps from which ergosterol was first isolated. Ergosterol is a component of yeast and other fungal cell membranes , serving many of the same functions that cholesterol serves in animal cells. [ 1 ]
Calcitriol was identified as the active form of vitamin D in 1971 and the drug was approved for medical use in the United States in 1978. [7] It is available as a generic medication . [ 12 ] In 2022, it was the 254th most commonly prescribed medication in the United States, with more than 1 million prescriptions.
22-Dihydroergocalciferol is a form of vitamin D, also known as vitamin D 4. [2] It has the systematic name (5Z,7E)-(3S)-9,10-seco-5,7,10(19)-ergostatrien-3-ol. [1] Vitamin D 4 is found in certain mushrooms, being produced from ergosta-5,7-dienol (22,23-dihydroergosterol) instead of ergosterol. [3]