Inaba M, Morii H
Second Department of Internal Medicine, Osaka City University Medical School.
Nihon Rinsho. 1992 Dec;50(12):2956-61.
With the application of biochemical technique came the discovery that vitamin D is metabolized sequentially to 25-hydroxyvitamin D in liver and then to 1.25-dihydroxyvitamin D (1.25D), the hormonal form of vitamin D, in kidney. The latter process is strictly controlled with the demand of calcium and phosphorus. The produced 1.25D binds its specific receptor probably located in the nuclei. With the application of modern tools of molecular biology came the discovery that vitamin D receptor (VDR), which belongs to steroid receptor family, acquires increased affinity for DNA when it binds to 1.25D and then VDR complexes bind to DNA with its two zinc-finger projections. VDR complexes recognize vitamin D responsive element on DNA, two tandemly repeated hexanucleotide sequences separated by three base pairs. Furthermore, to interact with the VDRE, VDR complexes require nuclear accessory factor, which might be retinoid X receptor (RXR). As above, molecular biology helps us to extend our knowledge in the field of vitamin D.
随着生化技术的应用，人们发现维生素D在肝脏中依次代谢为25-羟基维生素D，然后在肾脏中代谢为1,25-二羟基维生素D（1,25D），即维生素D的激素形式。后一过程受到钙和磷需求的严格控制。产生的1,25D与其可能位于细胞核中的特异性受体结合。随着现代分子生物学工具的应用，人们发现属于类固醇受体家族的维生素D受体（VDR）在与1,25D结合时对DNA的亲和力增加，然后VDR复合物通过其两个锌指突起与DNA结合。VDR复合物识别DNA上的维生素D反应元件，即由三个碱基对隔开的两个串联重复六核苷酸序列。此外，为了与VDRE相互作用，VDR复合物需要核辅助因子，其可能是视黄酸X受体（RXR）。如上所述，分子生物学帮助我们扩展了在维生素D领域的知识。
