HEPAIOCYTE MEMBRANE TRANSPORT MECHANISM OF VARIOUS SUBSTANCES

(1)以正常SD大鼠和卫材高胆红素尿酸大鼠（HEBR）肝脏为材料制备肝细胞微管膜泡（CMV）。Mg^<++> - atp酶和碱性磷酸酶活性在CMV中高度富集。[^3H]从注射[^3H]DELTA ALA的大鼠腹腔中纯化出双脲酸胆红素（BDG）。(2)用SD大鼠和EHBR肝脏CMV观察[^3H]BDG和[^3H]牛磺胆酸盐（TC）的转运，比较两种大鼠的转运差异。在SD大鼠CMV和EHBR CMV中均存在atp依赖性[^3H]TC转运。另一方面，[^3H]BDG转运不依赖于atp，并且在碳酸氢盐离子存在时增加。这种碳酸氢盐依赖性[^3H]BDG转运在EHBR CMV中也是完整的。(3)[^<14>C]普伐他汀（PS）是SD大鼠胆汁中的一种模式有机阴离子。然而，在EHBR中发现其胆汁排泄极度延迟。[^<14>C]研究了SD大鼠CMV对PS的转运，发现它是atp依赖性的。与体内PS的胆排泄缺陷相反，EHBR CMV中发现了正常的atp依赖性PS转运。(4)从这些结果。先天性黄疸EHBR中存在atp依赖性有机阴离子转运缺陷的假设尚未得到证实，并提示在大鼠肝细胞管膜上存在一种新的atp依赖性有机阴离子转运体。

(1)Canalicular membrane vesicles (CMV) of hepatocytes were prepared in pure form from the livers of normal SD rats and Eisai hyperbilirubinuric rats (HEBR). Mg^<++> -ATPase and alkaline phosphatase activities were highly enriched in the CMV.[ ^3H]Bilirubin diglucuronide (BDG) was purified from the hile of rats injected with [ ^3H]DELTA ALA.(2)Transport of [ ^3H]BDG and [ ^3H]taurocholate (TC) was observed using CMV from livers of SD rats and EHBR, and any differences of their transport between the 2 rat strains were compared. ATP-dependent [ ^3H]TC transport was present both in SD rat CMV and EHBR CMV.On the other hand, [ ^3H]BDG transport was not ATP-dependent and was increased in the presence of bicarbonate ion. This bicarbonate-dependent [ ^3H]BDG transport was also intact in EHBR CMV.(3)[^<14>C]Pravastatin (PS), One of model organic anions, is excreted in the bile of SD rats. However, its biliary excretion was found to be extremely delayd in EHBR.[^<14>C]PS transport by SD rat CMV was studied and found to be ATP-dependent. In contrast to the in vivo biliary excretion defect of PS, normal ATP-dependent PS transport was found in EHBR CMV.(4)From these results. the postulated defect in ATP-dependent organic anion transport in congenitally jaundiced EHBR was not confirmed and the presence of a novel ATP-dependent organic anion transporter was suugested on the canalicular membrane of rat hepatocytes.