What is "cholecalciferol"

vitamin D \vitamin D\ n. any of several chemically related fat-soluble vitamins that prevent rickets. It is found in fish-liver oils, egg yolks and milk. Component vitamin D2 is also called calciferol, and vitamin D3 is called cholecalciferol.

Syn: calciferol, ergocalciferol, cholecalciferol.

n. vitamin D3

Cholecalciferol (vitamin D) is one of the five forms of vitamin D. It is a secosteroid, that is, a steroid molecule with one ring open. Cholecalciferol is inactive: it is converted to its active form by two hydroxylations: the first in the liver, the second in the kidney, to form calcitriol, whose action is mediated by the vitamin D receptor, a nuclear receptor which regulates the synthesis of hundreds of enzymes and is present in virtually every cell in the body.