Turner R T, Howard G A, Puzas J E, Baylink D J, Knapp D R
Biochemistry. 1983 Mar 1;22(5):1073-6. doi: 10.1021/bi00274a012.
A metabolite of vitamin D has been isolated in pure form from incubation of 25-hydroxyvitamin D3 with embryonic chick calvarial cells that had been grown on Cytodex 1 microcarrier beads. The isolation involved dichloromethane extraction of the cells and incubation medium, followed by Sephadex LH-20 column chromatography and high-performance liquid chromatography of the extract. The metabolite was identified as 1 alpha,25-dihydroxyvitamin D3 by means of ultraviolet absorption spectroscopy, mass spectrometry, and sensitivity to oxidation by periodate. This metabolite was not produced by cell-free medium or by cells from embryonic chick liver, skin, or heart. In conclusion, (1) kidney cells are not unique in having 25-hydroxyvitamin D3:1 alpha-hydroxylase activity as previously believed and (2) vitamin D target tissues such as the skeleton may play a direct role in mediating the metabolism of 25-hydroxyvitamin D3 to 1 alpha,25-dihydroxyvitamin D3, a vitamin D metabolite active at those sites.
从在Cytodex 1微载体珠上生长的胚胎鸡颅骨细胞与25-羟基维生素D3孵育物中，已以纯形式分离出一种维生素D代谢物。分离过程包括用二氯甲烷萃取细胞和孵育培养基，然后对萃取物进行Sephadex LH - 20柱色谱和高效液相色谱分析。通过紫外吸收光谱、质谱以及对高碘酸盐氧化的敏感性，将该代谢物鉴定为1α,25 - 二羟基维生素D3。这种代谢物不是由无细胞培养基或来自胚胎鸡肝脏、皮肤或心脏的细胞产生的。总之，（1）肾细胞并不像以前认为的那样在具有25-羟基维生素D3:1α-羟化酶活性方面是独一无二的；（2）维生素D靶组织如骨骼可能在介导25-羟基维生素D3代谢为1α,25 - 二羟基维生素D3（一种在这些部位具有活性的维生素D代谢物）中起直接作用。
