Redefining Human Vitamin D Sufficiency:Back to the Basics

作     者：John S.Adams Jonathan Ramin Brandon Rafison Charles Windon Annika Windon Philip T.Liu 

作者机构：Orthopaedic Hospital Research CenterUCLA-Orthopaedic Hospital Department of Orthopaedic SurgeryDavid Geffen School of MedicineUCLA Department of MolecularCell and Developmental BiologyDivision of Life SciencesCollege of Letters and ScienceUCLA 

出 版 物：《Bone Research》 (骨研究（英文版）)

年 卷 期：2013年第1卷第1期

页      面：2-10页

核心收录：

学科分类：1002[医学-临床医学] 100210[医学-外科学(含：普外、骨外、泌尿外、胸心外、神外、整形、烧伤、野战外)] 10[医学] 

基　　金：NIH/NCRR/NCATS UCLA CTSI Grant Number UL1TR000124 NIH/NIAID Grant Number R01AI73539 

主　　题：metabolism endocrine autocrine hormone biomarkers 

摘      要：The role of the endocrine vitamin D pathway in regulating the serum calcium concentration in man is well described. In the presence of a low serum calcium level, the vitamin D metabolic pathway is called upon to produce more of the active vitamin D hormone, 1, 25-dihydroxyvitamin D （1, 25D）, via up-regulation of the CYP27b1-hydroxylase activity in the kidney. The consequence is mobilization of skeletal calcium stores to return the circulating calcium level back to the normal range. On the other hand, when the serum calcium level increases, endocrine forces move to suppress renal 1, 25D production and squelch bone resorption. It is now known that vitamin D metabolites also operate in an autocrine, paracrine and intracrine mode to control vitamin D receptor-directed biological responses at the tissue level. Because the metabolism and action of vitamin D occurs at the tissue level in this situation, use of circulating vitamin D metabolites and biomarkers to ascertain the local action of the vitamin D pathway is often misleading. This mini-review seeks to compare and contrast the operation of the vitamin D pathway at the endocrine and tissue level.