Vitamin-D Metabolism

Vitamin D can be either be obtained from nutrition or synthesised by our body in a reaction that requires Ultraviolet radiation. Ultraviolet radiation results in the conversion of 7-dehydrocholesterol to pre–vitamin D, which isomerizes to vitamin D in the skin. Vitamin D–binding protein transports vitamin D to the liver, where it undergoes 25-hydroxylation by CYP2R1. CYP27B1 further hydroxylates 25-hydroxyvitamin D, resulting in the formation of the active hormone 1,25-dihydroxyvitamin D.