We previously established that androgen glucuronides are effluxed by multidrug resistance–associated proteins 2 and 3. However, no data exist on the mechanism of hepatic uptake of these metabolites. The first goal of this study was to explore the role of hepatic uptake transporters and characterize transport kinetics of glucuronides of testosterone (TG), dihydrotestosterone (DHTG), androsterone (AG), and etiocholanolone (EtioG) using cell lines overexpressing organic anion transporting polypeptides (OATP1B1, OATP1B3, and OATP2B1). Using a quantitative proteomics-guided approach, we then estimated the fractional contribution of individual OATPs in hepatic uptake of these glucuronides. The transport screening assays revealed that the glucuronides were primarily taken up by OATP1B1 and OATP1B3. The K_m values for OATP1B1-mediated uptake were low for EtioG (6.2 µM) as compared with AG, TG, and DHTG (46.2, 56.7, and 71.3 µM, respectively), whereas the K_m value for OATP1B3-mediated uptake for EtioG, AG, DHTG, and TG were 19.8, 29.3, 69.6, and 110.4 µM, respectively. Both OATP1B1 and OATP1B3 exhibited the highest transport rate toward AG as compared with other glucuronides. When adjusted for the transporter abundance in human livers, EtioG and DHTG were predicted to be transported by both OATP1B1 and OATP1B3, whereas TG and AG were preferentially (>68%) transported by OATP1B3. Collectively, this report elucidates the mechanisms of hepatic uptake of androgen glucuronides. Perturbation of these processes by genetic polymorphisms, disease conditions, or drug interactions can lead to changes in enterohepatic recycling of androgens. TG and AG can be further investigated as potential biomarkers of OATP1B3 inhibition.

中文翻译：

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有机阴离子转运多肽介导的雄激素葡萄糖醛酸代谢产物的肝吸收。

我们先前确定雄激素葡萄糖醛酸苷被多药耐药相关蛋白2和3释放。但是，尚无关于肝脏代谢这些代谢物的机制的数据。这项研究的第一个目标是探索肝摄取转运蛋白的作用，并使用过表达有机阴离子转运多肽的细胞系来表征睾丸激素（TG），二氢睾酮（DHTG），雄甾酮（AG）和乙胆醇（EtioG）的葡萄糖醛酸苷的转运动力学。 （OATP1B1，OATP1B3和OATP2B1）。然后使用定量蛋白质组学指导的方法，我们估计了单个OATP在这些葡萄糖醛酸内酯的肝吸收中所占的比例。转运筛选试验表明，葡糖醛酸苷主要被OATP1B1和OATP1B3吸收。该ķ_米与AG，TG和DHTG相比，EtioG的OATP1B1介导的摄取值较低（6.2 µM）（分别为46.2、56.7和71.3 µM），而K _mOATP1B3介导的EtioG，AG，DHTG和TG摄取值分别为19.8、29.3、69.6和110.4 µM。与其他葡糖醛酸苷相比，OATP1B1和OATP1B3都表现出最高的AG转运速率。调整人体肝脏中的转运蛋白丰度后，预计EtioG和DHTG均由OATP1B1和OATP1B3转运，而TG和AG优先（> 68％）由OATP1B3转运。总体而言，该报告阐明了肝脏摄取雄激素葡糖醛酸的机制。遗传多态性，疾病状况或药物相互作用对这些过程的干扰会导致雄激素肠肝循环的改变。TG和AG可以进一步研究作为OATP1B3抑制的潜在生物标记。