calciferol(redirected from calciferol-25-hydroxylase)
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1. see vitamin D.
Activated ergosterol, the vitamin D of plant origin; it arises from ultraviolet irradiation of ergosterol, which is cleaved at the 9,10 bond and develops a double bond between C-10 and C-19; used in prophylaxis and treatment of vitamin D deficiency.
See vitamin D2.
Etymology: L, calx, lime, ferre, to bear
a fat-soluble, crystalline unsaturated alcohol produced by ultraviolet irradiation of ergosterol in plants. It is used as a dietary supplement in the prophylaxis and treatment of rickets, osteomalacia, and other hypocalcemic disorders. Also called ergocalciferol, oleovitamin D2, vitamin D2. See also rickets, viosterol.
calciferolA vitamin D derived from steroids by breaking the B ring’s 9-10 bond (e.g., cholecalciferol and ergocalciferol), which is produced by the body when exposed to UV light. Supplemental vitamin D3 reduces all-cause mortality, especially in elderly women, an effect not seen with vitamin D2, alfacalcidol or calcitriol (intrinsic vitamin D). However, too much or too little vitamin D is associated with increased mortality in a U-shaped risk curve.
calciferolVitamin D. A fat-soluble vitamin necessary for the absorption of calcium from the intestine. Deficiency causes RICKETS in infants and OSTEOMALACIA in adults.
vitamin D2a compound that has vitamin D properties and is obtained by ultraviolet irradiation of ergosterol.
calciferolvitamin D synthesized within skin under influence of sunlight; see ergocalciferol
vitamin d2; ergocalciferol.
a hepatic microsomal enzyme which controls the conversion of cholecalciferol to 25-hydroxycholecalciferol.