title: Regulation of vitamin D metabolism.
abstract: Fundamental to understanding the way in which perturbations in the vitamin D endocrine system can affect human health is an appreciation of the steps involved in the production of the well-recognized active hormonal form, 1,25-dihydroxyvitamin D(3). Thus this paper focuses first on the nature and regulation of the two enzymes responsible for the production of 1,25-dihydroxyvitamin D(3), the 25-hydroxylase in the liver and the 1α-hydroxylase in the kidney. The most important regulators of the 1α-hydroxylase in the kidney are 1,25-dihydroxyvitamin D(3) itself, parathyroid hormone and FGF23. The extent and importance of extra-renal, 1,25-dihydroxyvitamin D(3) synthesis is then considered. Finally the features of the 24R-hydroxylase, which produces 24R,25-dihydroxyvitamin D(3) in the kidney and is induced by and inactivated, 1,25-dihydroxyvitamin D(3)in target cells are described.
authors.affiliation: Department of Biochemistry, University of California, Riverside, CA 92521, USA. Helen.henry@ucr.edu.
authors.forename: Helen L
authors.initials: HL
authors.lastname: Henry
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3 / Q000378:metabolism; D000818:Animals; D019898:Autocrine Communication; D002117:Calcitriol / Q000378:metabolism; D053493:Cholestanetriol 26-Monooxygenase / Q000235:genetics / Q000378:metabolism; D025461:Feedback, Physiological; D000089703:Fibroblast Growth Factor-23; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D019899:Paracrine Communication; D015398:Signal Transduction; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism; D014807:Vitamin D / Q000378:metabolism*; D065668:Vitamin D3 24-Hydroxylase
chemical_list: C000717427:FGF23 protein, human; D014807:Vitamin D; D015650:24,25-Dihydroxyvitamin D 3; D000089703:Fibroblast Growth Factor-23; D013250:Steroid Hydroxylases; C406322:vitamin D 1-alpha hydroxylase; D053493:Cholestanetriol 26-Monooxygenase; D065668:Vitamin D3 24-Hydroxylase; D002117:Calcitriol