Role of extracellular Ca2+ in hepatic bile formation and taurocholate transport.
Role of extracellular Ca2+ in hepatic bile formation and taurocholate transport.
复制标题
细胞外 Ca2 在肝胆汁形成和牛磺胆酸盐转运中的作用。
DOI：
10.1152/ajpgi.1985.249.6.g711
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Clayton,LM
中科院分区：
文献类型：
--
作者：
Anwer,MS;Clayton,LM
在离体灌注大鼠肝脏和离体大鼠肝细胞中研究了细胞外Ca 2+在肝胆汁形成、胆汁膜通透性和牛磺胆酸盐（TC）转运中的作用，以确定胆汁胆汁酸排泄中细胞旁通透性的功能重要性。每个肝脏用含有1.3 mM Ca 2+的灌注液灌注1 h（对照期），然后用1.3、0.5、0.1、0.05、0.03或0.01 mM Ca 2+灌注1 h（实验期）。基础胆汁流量和胆汁排泄的TC显着下降，只有在和低于0.05 mM灌流液Ca 2+，并与增加胆汁灌流液浓度比的[3 H]菊粉（B/P菊粉比）。在0.05 mM时扩散渗透系数增加2倍，在0.03和0.01 mM灌注液Ca 2+时增加6倍，这可以解释B/P菊粉比率的增加。时间依赖性的增加，细胞与培养基中的菊粉浓度比的情况下，比在存在的Ca 2+。在离体肝细胞中测定的TC的肝摄取率和从灌流液中加入TC的消失和从预载肝细胞中TC的流出率没有受到Ca 2+去除的显着影响。在低灌注液Ca 2+下观察到的胆汁TC排泄下降可能是由于分泌的TC回流到灌注液中，然后再摄取。当TC摄取抑制剂（呋塞米和布美他尼）被添加到灌注液（0.03 mM Ca 2+）60分钟后，加入[14 C]TC灌注液放射性的积累，这是支持的。（250字处删节）
The role of extracellular Ca2+ in hepatic bile formation, biliary membrane permeability, and taurocholate (TC) transport was studied in isolated perfused rat livers and in isolated rat hepatocytes to determine the functional importance of paracellular permeability in biliary bile acid excretion. Each liver was perfused for 1 h with perfusate containing 1.3 mM Ca2+ (control period) followed by another hour with 1.3, 0.5, 0.1, 0.05, 0.03, or 0.01 mM Ca2+ (experimental period). Basal bile flow and biliary excretion of added TC declined significantly only at and below 0.05 mM perfusate Ca2+ and was associated with an increase in bile-to-perfusate concentration ratio of [3H]inulin (B/P inulin ratio). A twofold increase in the diffusional permeability coefficient at 0.05 mM and a sixfold increase at 0.03 and 0.01 mM perfusate Ca2+ could explain the increased in B/P inulin ratios. Time-dependent increases in cell-to-medium concentration ratios of inulin were less in the absence than in the presence of Ca2+. Hepatic uptake rates of TC determined in isolated hepatocytes and from perfusate disappearance of added TC and efflux rates of TC from preloaded hepatocytes were not significantly affected by Ca2+ removal. It is possible that the observed decline in biliary TC excretion at low perfusate Ca2+ is due to regurgitation of secreted TC back into the perfusate followed by reuptake. This was supported by an accumulation of perfusate radioactivity when TC uptake inhibitors (furosemide and bumetanide) were added to the perfusate (0.03 mM Ca2+) 60 min after the addition of [14C]TC.(ABSTRACT TRUNCATED AT 250 WORDS)