Fluid phase endocytosis by cultured rat hepatocytes and perfused rat liver: implications for plasma membrane turnover and vesicular trafficking of fluid phase markers.
Fluid phase endocytosis by cultured rat hepatocytes and perfused rat liver: implications for plasma membrane turnover and vesicular trafficking of fluid phase markers.
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培养的大鼠肝细胞和灌注的大鼠肝脏的液相内吞作用：对质膜周转和液相标记物的囊泡运输的影响。
DOI：
10.1073/pnas.83.24.9488
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发表时间：
1986
影响因子：
11.1
通讯作者：
VanDyke,RW
中科院分区：
文献类型：
--
作者：
Scharschmidt,BF;Lake,JR;Renner,EL;Licko,V;VanDyke,RW
肝细胞通过受体介导的内吞作用摄取各种配体，但关于肝细胞中通过内吞作用内化的液体体积或膜的量知之甚少。在这些研究中，我们利用放射性标记的菊粉来表征原代培养和灌注大鼠肝脏中大鼠肝细胞的液相内吞作用。培养肝细胞对菊糖的摄取与时间呈非线性关系，在最初的2分钟内发生得最快。培养肝细胞对菊糖的摄取和流出以及灌流大鼠肝脏对菊糖的摄取在动力学上与菊糖进入一个快速的（t1/2，1-2分钟）翻转（推测为内体）隔室，与细胞外空间交换内容物，约占肝细胞体积的3%，以及菊粉进入缓慢（t1/2，大于1小时）翻转的储存室并在其中浓缩。基于菊粉摄取，估计培养的肝细胞每小时内吞相当于其体积的20%或更多以及其质膜表面积的5倍或更多。无论是氯喹（1 mM），也不牛磺胆酸盐（200 μ M）影响菊粉处理培养细胞，而秋水仙碱（10 μ M）抑制转移到存储室大于50%。结合我们以前的观察，目前的研究结果表明，菊糖内吞跨基底外侧膜很大程度上（相当于80%）reproditated回到血浆中，与少量运输到细胞内的存储室（相当于18%）或胆汁（相当于2%）。菊粉通过这些途径的运输不受牛磺胆酸盐的影响，也不需要囊泡酸化，而转移到储存室或胆汁分泌需要完整的微管功能。
Hepatocytes take up a variety of ligands via receptor-mediated endocytosis, yet little is known regarding either the volume of fluid or the amount of membrane internalized via endocytosis in liver cells. In these studies, we have utilized radiolabeled inulin to characterize fluid phase endocytosis by rat hepatocytes in primary culture and perfused rat liver. Uptake of inulin by cultured hepatocytes was nonlinear with time, occurring most rapidly during the first 2 min. Inulin uptake and efflux in cultured hepatocytes and inulin uptake by perfused rat liver were kinetically compatible with the entry of inulin into a rapidly (t1/2, 1-2 min) turning-over (presumably endosomal) compartment that exchanged contents with the extracellular space and comprised approximately 3% of hepatocyte volume, as well as entry into and concentration of inulin within slowly (t1/2, greater than 1 hr) turning-over storage compartments. Based on inulin uptake, it is estimated that cultured hepatocytes endocytosed the equivalent of 20% or more of their volume and 5 or more times their plasma membrane surface area each hour. Neither chloroquine (1 mM) nor taurocholate (200 microM) affected inulin handling by cultured cells, whereas colchicine (10 microM) inhibited transfer to storage compartments by greater than 50%. In conjunction with our previous observations, the present findings suggest that inulin endocytosed across the basolateral membrane is largely (congruent to 80%) regurgitated back into plasma, with smaller amounts transported to intracellular storage compartments (congruent to 18%) or to bile (congruent to 2%). Transport of inulin via these pathways is unaffected by taurocholate and does not require vesicle acidification, whereas intact microtubular function is required for transfer to storage compartments or biliary secretion.