cholecalciferol - vitamin D
On WHO Model List of Essential Medicines : NO
Alternative names: -
Cholecalciferol is one of the five forms of vitamin D - vitamin D3. It is a secosteroid - a steroid molecule with one ring open. Vitamin D is important for the absorption of calcium from the stomach and for the functioning of calcium in the body.
Cholecalciferol is used to treat or prevent many conditions caused by a lack of vitamin D, especially conditions of the skin or bones.
However, vitamins, by definition are essential organic compounds which cannot be synthesised by the body and must be ingested - but cholecalciferol is synthesized by the body, and functions as a prehormone. Cholecalciferol itself is inactive: it is converted to its active form by two reactions: the first in the liver, the second in the kidney, to form calcitriol, whose action is mediated by the vitamin D receptor.
This receptor regulates the synthesis of hundreds of enzymes and is present in virtually every cell in the body.