Calcitroic acid

Calcitroic acid

Names
IUPAC name (3R)-3-[(1R,3aR,4E,7aR)- 4-[(2Z)-2-[(3R,5R)-3,5- Dihydroxy-2-methylene-cyclohexylidene]ethylidene] -7a-methyl-2,3,3a,5,6,7-hexahydro-1H -inden-1-yl]butanoic acid
Identifiers
CAS Number	71204-89-2
3D model (JSmol)	Interactive image
ChemSpider	4947800
PubChem CID	6443842
InChI InChI=1/C23H34O4/c1-14(11-22(26)27)19-8-9-20-16(5-4-10-23(19,20)3)6-7-17-12-18(24)13-21(25)15(17)2/h6-7,14,18-21,24-25H,2,4-5,8-13H2,1,3H3,(H,26,27)/b16-6+,17-7-/t14-,18+,19-,20+,21-,23-/m1/s1 Key: MBLYZRMZFUWLOZ-FEUSBDLHBT
SMILES O=C(O)C[C@@H](C)[C@H]3CC[C@H]2C(=C\C=C1/C(=C)[C@H](O)C[C@@H](O)C1)\CCC[C@@]23C
Properties
Chemical formula	C23H34O4
Molar mass	374.514

Calcitroic acid (1α-hydroxy-23-carboxy-24,25,26,27-tetranorvitamin D₃) is a major metabolite of 1α,25-dihydroxyvitamin D₃ (calcitriol). Around 1980, scientists first reported the isolation of calcitroic acid from the aqueous extract of radioactively treated animals' livers and intestines. Subsequent researches confirmed calcitroic acid to be a part of enterohepatic circulation. Often synthesized in the liver and kidneys, calcitroic acid is generated in the body after vitamin D is first converted into calcitriol, an intermediate in the fortification of bone through the formation and regulation of calcium in the body. These pathways managed by calcitriol are thought to be inactivated through its hydroxylation by the enzyme CYP24A1, also called calcitriol 24-hydroxylase.Specifically, It is thought to be the major route to inactivate vitamin D metabolites. The hydroxylation and oxidation reactions will yield either calcitroic acid via the C24 oxidation pathway or 1,25(OH2)D3-26,23-lactone via the C23 lactone pathway.

Hydroxylation and further metabolism of calcitriol in the liver and the kidneys yields calcitroic acid, a water-soluble compound that is excreted in bile.

In case where a higher concentration of this acid is used in vitro, studies determined that calcitroic acid binds to vitamin D receptor (VDR) and induces gene transcription.

The compound has been prepared in the laboratory.