All of the following statements about the vitamin D-regulated of calcium ions are true EXCEPT
A) ergocalciferol is normally converted to cholecalciferol in a reaction requiring ultraviolet light.
B) irradiated ergosterol is added to commercial milk because it can replace cholecalciferol.
C) cholecalciferol is 25-hydroxylated in the liver.
D) hydroxycholecalciferol is further hydroxylated in kidney to form the active hormone.
E) excess vitamin D can lead to hypercalcemia, which in turn can result in calcification of soft tissue.

Question

Quizplus · Accepted Answer

Ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3) are different forms of vitamin D. Ergocalciferol is derived from plants and fungi, while cholecalciferol is produced in the skin of animals, including humans, when exposed to ultraviolet light. Ergocalciferol does not need to be converted to cholecalciferol; it is an active form of vitamin D on its own.

All of the Following Statements About the Vitamin D-Regulated of Calcium