Transport of vitamin D metabolites.
Transport of vitamin D metabolites.
复制标题
维生素 D 代谢物的运输。
DOI：
10.1097/00003086-197907000-00040
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发表时间：
1979
影响因子：
4.2
通讯作者：
J. Haddad
中科院分区：
文献类型：
--
作者：
J. Haddad
维生素D及其代谢产物与人血清中的α球蛋白（DBP）结合。这种载体蛋白以比维生素D或1，25（OH）2D更高的亲和力结合25-OHD和24，25（OH）2D，但这种结合对维生素D结构具有高度特异性。载体机制似乎是独特的，因为它是一个高亲和力和高容量的系统，能够结合多达120，000 IU的生物活性/升血浆。DBP显然与组特异性成分相同，迄今为止，在检测的约75，000份人血清中尚未鉴定出DBP缺乏状态。肝脏似乎是合成DBP的场所，妊娠期间和雌激素-孕酮治疗期间血清DBP水平升高。然而，在各种矿物质稳态紊乱中，血清DBP水平是正常的。已经鉴定了两种维生素D代谢物的组织结合蛋白。在所有有核组织中发现了一种在5-6S处沉积的蛋白质，其表现出类似于DBP的配体偏好。这种组织结合蛋白似乎是血清DBP与组织蛋白的复合物，该组织蛋白是热不稳定的，并且没有显示出结合维生素D甾醇的能力。目前尚不清楚这种血清DBP和组织蛋白复合物的生理作用（如果有的话）。另一种组织结合组分是仅在识别的靶组织中发现的3-4S蛋白，其对1，25（OH）2 D显示出高结合亲和力和特异性。它似乎是受体-1，25（OH）2D迁移到细胞核中的受体，导致mRNA的生物合成，该mRNA编码影响靶组织中钙和磷转运的产物。
Vitamin D and its metabolites are bound to an alpha globulin (DBP) in human serum. This carrier protein binds 25-OHD and 24,25(OH)2D with higher affinity than vitamin D or 1,25(OH)2D, but the binding is highly specific for the vitamin D structure. The carrier mechanism appears to be unique in that it is a high affinity and high capacity system, capable of binding as much as 120,000 IU of biological activity per liter of plasma. DBP is apparently identical to group-specific component, and a DBP-deficient state has not been identified among approximately 75,000 human sera examined thus far. The liver appears to be the site for synthesis of DBP, and serum DBP levels are increased during pregnancy and during estrogen-progesterone therapy. However, in a variety of disorders of mineral homeostasis, serum DBP levels are normal. Two tissue binding proteins for vitamin D metabolites have been identified. One protein, sedimenting at 5-6S, has been found in all nucleated tissues, and exhibits a ligand preference similar to DBP. This tissue binding protein appears to be a complex of serum DBP with a tissue protein which is heat-labile, and which shows no capacity for binding vitamin D sterols. The physiologic role, if any, for this complex of serum DBP and tissue protein is not presently understood. The other tissue binding component is a 3-4S protein found only in recognized target tissues, and which shows a high binding affinity and specificity for 1,25(OH)2 D. It appears to be the receptor in the receptor-1,25(OH)2D migration to the nucleus, leading to the biosynthesis of mRNA which codes for products which affect calcium and phosphorus transport in target tissues.