24,25-Dihydroxycholecalciferol
Encyclopedia
24,25-Dihydroxycholecalciferol, also known as 24,25-dihydroxyvitamin D3 and (24R)-hydroxycalcidiol (abbreviated as 24(R),25-(OH)2D3), is a compound which is closely related to 1,25-dihydroxyvitamin D3, the active form of vitamin D3
, but like vitamin D3 itself and 25-hydroxyvitamin D3 is inactive as a hormone
both in vitro
and in vivo
.
(25-hydroxyvitamin D3-24-hydroxylase), which appears to be "a multicatalytic enzyme catalyzing most, if not all, of the reactions in the C-24/C-23 pathway of 25-OH-D3 metabolism." It has been proposed that 24,25-dihydroxyvitamin D3 is a metabolite of 25-hydroxyvitamin D3 which is destined for excretion.
It is not known whether the compound might also have some physiologically significant activity. Some evidence of a possible receptor has been obtained.
Cholecalciferol
Cholecalciferol is a form of vitamin D, also called vitamin D3 or calciol.It is structurally similar to steroids such as testosterone, cholesterol, and cortisol .-Forms:Vitamin D3 has several forms:...
, but like vitamin D3 itself and 25-hydroxyvitamin D3 is inactive as a hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
both in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
and in vivo
In vivo
In vivo is experimentation using a whole, living organism as opposed to a partial or dead organism, or an in vitro controlled environment. Animal testing and clinical trials are two forms of in vivo research...
.
Formation and significance
24,25-dihydroxyvitamin D3 is formed from 25-hydroxyvitamin D3 by the action of P450cc24CYP24A1
1,25-dihydroxyvitamin D3 24-hydroxylase, mitochondrial is an enzyme that in humans is encoded by the CYP24A1 gene.This gene encodes a member of the cytochrome P450 superfamily of enzymes...
(25-hydroxyvitamin D3-24-hydroxylase), which appears to be "a multicatalytic enzyme catalyzing most, if not all, of the reactions in the C-24/C-23 pathway of 25-OH-D3 metabolism." It has been proposed that 24,25-dihydroxyvitamin D3 is a metabolite of 25-hydroxyvitamin D3 which is destined for excretion.
It is not known whether the compound might also have some physiologically significant activity. Some evidence of a possible receptor has been obtained.