. "\"The chemical reactions and pathways resulting in the breakdown of vitamin D, any of a group of related, fat-soluble compounds that are derived from delta-5,7 steroids and play a central role in calcium metabolism. Specific forms of vitamin D include calciferol (ergocalciferol; vitamin D2) and cholecalciferol (calciol; vitamin D3).\" [CHEBI:27300, GOC:mah, ISBN:0471331309]" . . "vitamin D catabolic process" . "vitamin D breakdown" . "vitamin D catabolism" . "vitamin D degradation" . . . . . "cholecalciferol biosynthesis" . "cholecalciferol biosynthetic process" . "ergocalciferol biosynthesis" . "ergocalciferol biosynthetic process" . "calciferol catabolic process" . "calciferol catabolism" . . . . . . . . . . . . . . .