Kumar R, Schaefer J, Grande J P, Roche P C
Department of Medicine, Mayo Clinic and Foundation, Rochester, Minnesota 55905.
Am J Physiol. 1994 Mar;266(3 Pt 2):F477-85. doi: 10.1152/ajprenal.1994.266.3.F477.
The precise localization of the calcitriol (1 alpha,25-dihydroxyvitamin D3) receptor (VDR) and the 25-hydroxyvitamin D3 [25(OH)D3] 24-hydroxylase cytochrome P-450 in the human kidney is unknown. Using newly developed polyclonal antibodies against the human VDR, we demonstrate that the receptor is present in cells of the distal tubule, the collecting duct, the proximal tubule, and in the parietal epithelial cells of the glomerulus. In the distal tubule and collecting duct not all cells contain epitopes for the receptor. The protein is not detected in glomerular capillaries, in the glomerular mesangium, in the interstitium, or in blood vessels. Specific polyclonal antibodies directed against the 25(OH)D3 24-hydroxylase cytochrome P-450 demonstrate epitopes for the cytochrome in cells of the proximal tubule, the distal tubule, glomerular parietal epithelial cells, and mesangial cells. The protein is absent from interstitial cells. Calbindin D28k is present exclusively in principal cells of the distal tubule and collecting duct. In the human kidney, the VDR is present in cells where vitamin D-inducible proteins are found; conversely it is absent from cells where vitamin D-dependent proteins are not present.
骨化三醇（1α，25 - 二羟维生素D3）受体（VDR）和25 - 羟维生素D3 [25(OH)D3] 24 - 羟化酶细胞色素P - 450在人肾中的精确定位尚不清楚。使用新开发的针对人VDR的多克隆抗体，我们证明该受体存在于远端小管、集合管、近端小管的细胞以及肾小球的壁层上皮细胞中。在远端小管和集合管中，并非所有细胞都含有该受体的表位。在肾小球毛细血管、肾小球系膜、间质或血管中未检测到该蛋白。针对25(OH)D3 24 - 羟化酶细胞色素P - 450的特异性多克隆抗体在近端小管、远端小管、肾小球壁层上皮细胞和系膜细胞中显示出该细胞色素的表位。间质细胞中不存在该蛋白。钙结合蛋白D28k仅存在于远端小管和集合管的主细胞中。在人肾中，VDR存在于发现维生素D诱导蛋白的细胞中；相反，在不存在维生素D依赖性蛋白的细胞中则不存在。
