Terdoslavich Michela, de Graaf Inge A M, Proost Johannes H, Cocolo Alessandra, Passamonti Sabina, Groothuis Geny M M
Department of Life Sciences, University of Trieste, via L. Giorgieri, 1, 34127 Trieste, Italy.
Drug Metab Lett. 2012 Sep 1;6(3):165-73. doi: 10.2174/1872312811206030003.
Hepatic disposition of bromosulfophthalein (BSP), bilirubin and bile salts partially overlap, as these anions share both uptake and excretion mechanisms. Multiple organic anion transporters mediate hepatic BSP uptake, i.e. members of the SLCO and SLC22 gene families and bilitranslocase (TCDB #2.A.65.1.1). This study aimed at evaluating the relative contribution of bilitranslocase in BSP uptake in precision-cut human and rat liver slices. To this purpose, two different anti-sequence bilitranslocase antibodies were used as specific, functional inhibitors of bilitranslocase. The intact liver physiology was accurately reproduced in this BSP uptake assay, since uptake was strongly temperature-dependentand inhibited by hepatotropic organic anions, such as 50 nM bilirubin, 1 μM nicotinic acid, 2 μM digoxin, 5 μMindocyanine green and 100 μM taurocholate. The bilitranslocase antibodies inhibited BSP uptake both in rat and human liver slices. The combined use of bilitranslocase antibodies and taurocholate caused additive-type inhibition, confirming that bilitranslocase is not a bile salt transporter; by contrast, bilirubin caused no additive-type inhibition. In conclusion this data, indicate the role of the bilirubin transporter bilitranslocase as one of the transporters involved in the uptake of anions like BSP in parallel with other organic anion carriers. Moreover this data indicate the value of precision-cut liver slices for phenotypic drug uptake studies.
溴磺酞钠（BSP）、胆红素和胆盐在肝脏中的处置存在部分重叠，因为这些阴离子共享摄取和排泄机制。多种有机阴离子转运体介导肝脏对BSP的摄取，即溶质载体有机阴离子转运体（SLCO）和溶质载体22（SLC22）基因家族的成员以及胆红素转运蛋白（转运蛋白分类数据库#2.A.65.1.1）。本研究旨在评估胆红素转运蛋白在精密切割的人及大鼠肝切片中对BSP摄取的相对贡献。为此，使用了两种不同的抗序列胆红素转运蛋白抗体作为胆红素转运蛋白的特异性功能抑制剂。在该BSP摄取试验中准确再现了完整的肝脏生理学，因为摄取强烈依赖温度，并受到亲肝有机阴离子的抑制，如50 nM胆红素、1 μM烟酸、2 μM地高辛、5 μM吲哚菁绿和100 μM牛磺胆酸盐。胆红素转运蛋白抗体在大鼠和人肝切片中均抑制了BSP摄取。胆红素转运蛋白抗体和牛磺胆酸盐的联合使用导致加和型抑制，证实胆红素转运蛋白不是胆盐转运体；相比之下，胆红素未引起加和型抑制。总之，这些数据表明胆红素转运蛋白作为与其他有机阴离子载体并行参与摄取BSP等阴离子的转运体之一的作用。此外，这些数据表明精密切割肝切片在表型药物摄取研究中的价值。
