Translations:Ergocalciferol/12/en

Like cholecalciferol, ergocalciferol is inactive by itself. It requires two hydroxylations to become active: the first in the liver by CYP2R1 to form 25-hydroxyergocalciferol (ercalcidiol or 25-OH D₂), and the second in the kidney by CYP27B1, to form the active 1,25-dihydroxyergocalciferol (ercalcitriol or 1,25-(OH)₂D₂), which activates the vitamin D receptor. Unlike cholecalciferol, 25-hydroxylation is not performed by CYP27A1 for ergocalciferol.