title: Vitamin D: metabolism.
abstract: The biologically active metabolite of vitamin D, 1,25(OH)(2)D(3), affects mineral homeostasis and has numerous other diverse physiologic functions including effects on growth of cancer cells and protection against certain immune disorders. This article reviews the role of vitamin D hydroxylases in providing a tightly regulated supply of 1,25(OH)(2)D(3). The role of extrarenal 1α(OH)ase in placenta and macrophages is also discussed, as well as regulation of vitamin D hydroxylases in aging and chronic kidney disease. Understanding specific factors involved in regulating the hydroxylases may lead to the design of drugs that can selectively modulate the hydroxylases. The ability to alter levels of these enzymes would have therapeutic potential for the treatment of various diseases, including bone loss disorders and certain immune diseases.
authors.affiliation: Department of Biochemistry and Molecular Biology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA. christak@umdnj.edu
authors.forename: Sylvia
authors.initials: S
authors.lastname: Christakos
authors.forename: Dare V
authors.initials: DV
authors.lastname: Ajibade
authors.forename: Puneet
authors.initials: P
authors.lastname: Dhawan
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Fechner
authors.forename: Leila J
authors.initials: LJ
authors.lastname: Mady