Vitamin D Council Glossary

1α(OH)D2
1α-hydroxyvitamin D2. see Doxercalciferol.
1α(OH)D3
1α-hydroxyvitamin D3. see Alphacalcidiol.
1,25(OH)2D3
1,25-dihydroxyvitamin D3. see calcitriol.
19-Nor-1,25-(OH)2D2
19-nor-1,25-dihydroxyvitamin D2. see Paricalcitol.
22-oxacalcitriol (OCT)
Vitamin D analogue similar to 1,25(OH)2D3, differing only due to an oxygen atom replacing carbon-22 on the side chain. OCT has demonstrated an ability to suppress PTH synthesis and secretion, both in vitro and in vivo.
23,25(OH)2D3
23,25-hydroxyvitamin D3. Vitamin D metabolite.
24,25(OH)D2
24,25-hydroxyvitamin D2.
24,25(OH)D3
24,25-hydroxyvitamin D3. Vitamin D metabolite.
24,25(OH)2D2
24,25-dihydroxyvitamin D2.
24,25(OH)2D3
24,25-dihydroxycholecalciferol D3. Vitamin D metabolite that is biologically active in cartilage.
24R,25(OH)2D3
24R,25-dihydroxyvitamin D3. A natural vitamin D metabolite essential for development of normal bone integrity and healing of fractures.
24S,25-(OH)2D3
24S,25-dihydroxyvitamin D3. Synthetic epimer (mirror image) of 24R,25-dihydroxyvitamin D3.
25(OH)D or 25(OH)D3
25-hydroxyvitamin D, or 25-hydroxycholecalciferol. see calcidiol. When a person refers to their "25(OH)D" they are referring to their blood calcidiol level.
25(OH)D3-1-hydroxylase
Enzyme found in the kidneys, where it converts 25(OH)D to 1,25(OH)2D.
25-hydroxyvitamin D
see calcidiol.
25-hydroxyvitamin D test
Also known as 25(OH)D test. Test that measures the amount of calcidiol circulating in the blood. The most accurate measure of the amount of vitamin D in the body. See blood calcidiol level.
28-kilodalton calbindin-D
Vitamin D-induced calcium-binding protein.
7-dehydrocholesterol (7-DHC)
Provitamin D3. A cholesterol precursor whose presence in the skin enables the synthesis of vitamin D3 cholecalciferol from ultraviolet B rays in sunlight.
7-dehydrositosterol
Sterol which serves as a precursor for sitocalciferol (vitamin D5).