胆汁酸和盐类的回收
中文名称
通路描述
肝脏每日释放的 20-40 克胆汁酸和盐类中，除了约 0.5 克外，几乎全部被肠上皮细胞吸收，返回肝脏，并被重新利用。这一回收过程涉及一系列转运过程：由 ASBT（SLC10A2）介导的肠上皮细胞摄取，由肠肝循环蛋白（I-BABP - FABP6）介导的肠上皮细胞胞质穿越，由 MRP3（ABCC3）介导的肠上皮细胞外排，与白蛋白复合物通过门静脉血运输，以及由 Na+-taurocholate 转运蛋白（NTPC - SLC10A1）和少量有机阴离子转运蛋白 A、C 和 8（OATPA - SLCO1A2, OATPC - SLCO1B1, 和 OATP-8 - SLCO1B3）介导的肝细胞摄取。一旦返回肝细胞胞质，由肠道细菌作用分泌的胆汁酸（通过共酶 A 活化）与辅酶 A 结合，然后与甘氨酸或牛磺酸偶联，再生胆汁酸以供重新导出到胆汁，由胆汁酸泵介导，ABCB11（Kullak-Ublick et al. 2004; Mihalik et al. 2002; Trauner and Boyer 2003）。未修饰的胆汁酸返回肝细胞胞质时，可由 ABCB11 再次导出，无需进一步修饰。
英文描述
Recycling of bile acids and salts Of the 20-40 grams of bile salts released daily by the liver, all but approximately 0.5 grams are reabsorbed from the intestine, returned to the liver, and re-used. This recycling involves a series of transport processes: uptake by enterocytes mediated by ASBT (SLC10A2), traversal of the enterocyte cytosol mediated by ileal bile acid binding protein (I-BABP - FABP6), efflux from enterocytes mediated by MRP3 (ABCC3), travel through the portal blood as a complex with albumin, and uptake by hepatocytes mediated by Na+-taurocholate transporting protein (NTPC - SLC10A1) and, to a lesser extent by organic anion transporting proteins A, C, and 8 (OATPA - SLCO1A2, OATPC - SLCO1B1, and OATP-8 - SLCO1B3). Once returned to the hepatocyte cytosol, bile acids (generated in the intestine by the action of bacteria on secreted bile salts) are activated by conjugation with coenzyme A, then coupled to glycine or taurine, regenerating bile salts for re-export into the bile, mediated by the bile salt export pump, ABCB11 (Kullak-Ublick et al. 2004; Mihalik et al. 2002; Trauner and Boyer 2003). Unmodified bile salts returned to the hepatocyte cytosol can be re-exported by ABCB11 without further modification.
所含基因
18 个基因