The natural, active form of

vitamin D Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most important compo ...

calcitriol Calcitriol is a hormone and the active form of vitamin D, normally made in the kidney. It is also known as 1,25-dihydroxycholecalciferol. It binds to and activates the vitamin D receptor in the nucleus of the cell, which then increases the exp ...

(1,25-dihydroxycholecalciferol). This molecule and other naturally occurring forms of vitamin D, including its precursors and metabolites, have been modified to synthesize

pharmaceuticals Medication (also called medicament, medicine, pharmaceutical drug, medicinal product, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the ...

with potentially greater, or selective, therapeutic actions.

Types

These include: * Alfacalcidol *

Calcipotriol Calcipotriol, also known as calcipotriene and sold under the brand name Dovonex among others, is a synthetic derivative of calcitriol, a form of vitamin D. It is used in the treatment of psoriasis. It was patented in 1985 and approved for me ...

(calcipotriene) * Doxercalciferol * Falecalcitriol * Paricalcitol * Tacalcitol

Mechanisms

These modified vitamin D analogues have a

side chain In organic chemistry and biochemistry, a side chain is a substituent, chemical group that is attached to a core part of the molecule called the "main chain" or backbone chain, backbone. The side chain is a hydrocarbon branching element of a mo ...

or other modifications. They aim to reduce the classical renal and intestinal effects of calcitriol on

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

and

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

homeostasis, from its effects on other biologic processes. They target

cell proliferation Cell proliferation is the process by which ''a cell grows and divides to produce two daughter cells''. Cell proliferation leads to an exponential increase in cell number and is therefore a rapid mechanism of tissue growth. Cell proliferation ...

and differentiation, especially in skin, or other effects in the parathyroid gland (secondary

hyperparathyroidism Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands ( primary hyperparathyroidism) or as response to external stimuli ( secondary hyperparathyroi ...

) or bone cells.

References

{{Vitamin D receptor modulators Drugs by mechanism of action Vitamin D