Cholecalciferol (Vitamin D3, Cholecalciferol, Colecalciferol) is a form of vitamin D, binds and activates a H305F/H397Y mutant vitamin D receptor (VDR) withEC50of 300 nM. In vitro
Vitamin D3 is a fat-soluble vitamin that helps your body absorb calcium and phosphorus. Vitamin D3, a precursor in the 1α,25- dihydroxyvitamin D3 biosynthetic pathway, which does not activate wild-type hVDR. It binds and activates H305F/H397Y variant hVDR ,with 70 fold activation in compare to wide-type hVDR. Epidemiological studies and work on experimental animals strongly suggest a protective effect of cholecalciferol vitamin D3 (1,25(OH)2D3) against colon cancer and several other cancers.
In vivo
With UV-radiation, vitamin D3 is synthesized in the skin from the precursors 7-dehydro-cholesterole and provitamin D3. In the liver, vitamin D3 is transformed to 25-hydroxyvitamin D3. Six cytochrome P450 hydroxylases can exhibit this 25-hydroxylation, with the main enzyme being CYP27A1 (25-hydroxylase). The subsequent step is a 1alpha-hydroxylation by CYP27B1 (1-hydroxylase), which produces the most active form of vitamin D3, 1,25-dihydroxyvitamin-D3. This metabolite is inactivated by a 24-hydroxylation by CYP24 (24-hydro-xylase). Vitamin D3 is used for prevention of mortality in adults. However, Vitamin D3 combines with calcium increased the risk of nephrolithiasis. Cell Data
