PDF(Pubmed)
Abstract：
The synthetic analogs of regulatory peptides radiolabeled with adequate radionuclides are perspective tools in nuclear medicine. However, undesirable uptake and retention in the kidney limit their application. Specific in vitro methods are used to evaluate undesirable renal accumulation. Therefore, we investigated the usefulness of freshly isolated rat renal cells for evaluating renal cellular uptake of receptor-specific peptide analogs. Special attention was given to megalin as this transport system is an important contributor to the active renal uptake of the peptides. Freshly isolated renal cells were obtained from native rat kidneys by the collagenase method. Compounds with known accumulation in renal cells were used to verify the viability of cellular transport systems. Megalin expressions in isolated rat renal cells were compared to two other potential renal cell models by Western blotting. Specific tubular cell markers were used to confirm the presence of proximal tubular cells expressing megalin in isolated rat renal cell preparations by immunohistochemistry. Colocalization experiments on isolated rat kidney cells confirmed the presence of proximal tubular cells bearing megalin in preparations. The applicability of the method was tested by an accumulation study with several analogs of somatostatin and gastrin labeled with indium-111 or lutetium-177. Therefore, isolated rat renal cells may be an effective screening tool for in vitro analyses of renal uptake and comparative renal accumulation studies of radiolabeled peptides or other radiolabeled compounds with potential nephrotoxicity.
摘要：
用足够的放射性核素放射性标记的调节肽的合成类似物是核医学中的前瞻性工具。然而,不希望的摄取和在肾中的滞留限制了它们的应用。使用特定的体外方法来评估不期望的肾积累。因此,我们研究了新鲜分离的大鼠肾细胞对评估肾细胞摄取受体特异性肽类似物的有用性.特别注意megalin，因为该运输系统是肽的活跃肾脏摄取的重要因素。通过胶原酶方法从天然大鼠肾脏获得新鲜分离的肾细胞。使用在肾细胞中具有已知积累的化合物来验证细胞转运系统的活力。通过Western印迹将分离的大鼠肾细胞中的Megalin表达与其他两种潜在的肾细胞模型进行比较。通过免疫组织化学，使用特定的肾小管细胞标记物确认在分离的大鼠肾细胞制剂中存在表达megalin的近端肾小管细胞。在分离的大鼠肾细胞上进行的共定位实验证实了制剂中存在带有megalin的近端肾小管细胞。该方法的适用性通过积累研究进行了测试，该研究使用了用铟111或lutum177标记的生长抑素和胃泌素的几种类似物。因此,分离的大鼠肾细胞可能是一种有效的筛选工具，用于体外分析放射性标记的肽或其他具有潜在肾毒性的放射性标记的化合物的肾脏摄取和比较肾脏积累研究。
