1,25-Dihydroxycholecalciferol: Identification of the Proposed Active Form of Vitamin D3 in the Intestine

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Science  02 Jul 1971:
Vol. 173, Issue 3991, pp. 51-54
DOI: 10.1126/science.173.3991.51


The major polar metabolite of cholecalciferol (vitamin D3) present in chick intestinal mucosa has been chemically characterized by mass spectrometric analysis to have a molecular formula of C27H4403 and a structure of 1,25-dihydroxycholecalciferol. This compound, which is produced in the kidney from 25-hydroxycholecalciferol, has been previously shown to be from 4 to 13 times as active as cholecalciferol in stimulating intestinal calcium transport. 1,25-Dihydroxycholecalciferol (previously designated metabolite 4B in this (laboratory) probably represents the biologically active form of cholecalciferol in the intestine.