title: Calcemic actions of vitamin D: effects on the intestine, kidney and bone.
abstract: The analysis of mice that lack systemically the actions of the active form of vitamin D, 1,25(OH)₂D, has shown that 1,25(OH)₂D is an essential regulator of calcium homeostasis and that its actions are aimed at maintaining serum calcium levels within narrow limits. Especially the stimulation of intestinal calcium transport by 1,25(OH)₂D is important for calcium and bone homeostasis. The involved transporters are however still elusive. The targeted deletion of 1,25(OH)₂D action in chondrocytes has provided compelling evidence for a paracrine control of bone development and endocrine regulation of phosphate homeostasis by 1,25(OH)₂D. Targeting vitamin D receptor (VDR) function in other tissues will further enhance our understanding of the cell-type specific action of 1,25(OH)₂D. In this review, we will discuss the current understanding and remaining questions concerning the calcemic actions of 1,25(OH)₂D in the intestine, kidney and bone, with special focus on the evidence obtained by the use of transgenic mouse models.
authors.affiliation: Laboratory of Experimental Medicine & Endocrinology, Katholieke Universiteit Leuven, Herestraat 49, Leuven, Belgium. liesbet.lieben@med.kuleuven.be
authors.forename: Liesbet
authors.initials: L
authors.lastname: Lieben
authors.forename: Geert
authors.initials: G
authors.lastname: Carmeliet
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Masuyama
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000378:metabolism*; D020013:Calcium Signaling; D002136:Calcium, Dietary / Q000378:metabolism*; D006706:Homeostasis; D006801:Humans; D007408:Intestinal Absorption; D007413:Intestinal Mucosa / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D014807:Vitamin D / Q000378:metabolism*
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D