Vitamin D metabolism involves Vitamin D receptor (VDR) , Vitamin D binding protein (DBP) , and enzymes such as CYP2R1, CYP27B1, and CYP24A1 . VDR regulates gene expression related to calcium and phosphate balance and is present in the nuclei of cells in various tissues including the intestines, kidneys, and bones . DBP, abundant in the serum, transports vitamin D metabolites to target tissues. Enzymes like CYP2R1 and CYP27B1, located in the liver and kidneys respectively, activate vitamin D, while CYP24A1, found in various tissues, catabolizes it to maintain and regulate its levels .