Berr F, Simon F R, Reichen J
Am J Physiol. 1984 Oct;247(4 Pt 1):G437-43. doi: 10.1152/ajpgi.1984.247.4.G437.
Ethynylestradiol impairs bile flow and bile salt maximum secretory rate in rats, implying a secretory defect. In addition, Na-K-ATPase activity is decreased in liver surface membranes, suggesting abnormalities at the sinusoidal as well as the canalicular membrane. We investigated whether ethynylestradiol pretreatment affects bile salt uptake and Na-K pump function in isolated rat hepatocytes. Ethynylestradiol-treated cells were functionally intact as assayed with trypan blue exclusion, lactate dehydrogenase release, and oxygen consumption. Initial taurocholate uptake velocity was reduced by 73% in ethynylestradiol-treated hepatocytes [Vmax, 1.0 +/- 0.1 vs. 3.7 +/- 0.2 mumol X min-1 X (10(6) cells)-1; P less than 0.001; Km, 34 +/- 5 vs. 33 +/- 3 microM]. Na-K-ATPase activity in cell homogenates (36 +/- 5 vs. 27 +/- 4 mumol Pi X h-1 X mg prot-1; P less than 0.05), ouabain-suppressible rubidium-86 influx [6.8 +/- 1.1 vs. 4.8 +/- 1.0 nmol K+ X min-1 X (10(6) cells)-1; P less than 0.05], and intracellular potassium concentration (126 +/- 10 vs. 110 +/- 16 mmol/l; P less than 0.05) were reduced after ethynylestradiol. Taurocholate uptake measured at different temperatures between 25 degrees and 37 degrees was linear when plotted according to Arrhenius. The energy of activation was increased by 40% in ethynylestradiol-treated hepatocytes [17 +/- 4 vs. 23 +/- 4 kcal X mol-1 X (10(6) cells)-1; P less than 0.05], consistent with decreased membrane fluidity. These data suggest the possibility that during ethynylestradiol-induced cholestasis a disorder of the sinusoidal domain, caused perhaps by ethynylestradiol-induced alterations in membrane lipid composition, is an important contributing factor.
乙炔雌二醇会损害大鼠的胆汁流动和胆盐最大分泌率，这意味着存在分泌缺陷。此外，肝表面膜中的钠钾ATP酶活性降低，表明肝血窦膜和胆小管膜均存在异常。我们研究了乙炔雌二醇预处理是否会影响分离的大鼠肝细胞中胆盐的摄取和钠钾泵功能。用台盼蓝排斥试验、乳酸脱氢酶释放试验和耗氧量试验检测，发现经乙炔雌二醇处理的细胞功能完整。经乙炔雌二醇处理的肝细胞中，牛磺胆酸盐的初始摄取速度降低了73%[最大摄取速度（Vmax），1.0±0.1对3.7±0.2 μmol·min⁻¹·(10⁶个细胞)⁻¹；P<0.001；米氏常数（Km），34±5对33±3 μM]。经乙炔雌二醇处理后，细胞匀浆中的钠钾ATP酶活性（36±5对27±4 μmol无机磷酸·h⁻¹·mg蛋白⁻¹；P<0.05）、哇巴因可抑制的⁸⁶铷内流[6.8±1.1对4.8±1.0 nmol钾⁺·min⁻¹·(10⁶个细胞)⁻¹；P<0.05]以及细胞内钾浓度（126±10对110±16 mmol/L；P<0.05）均降低。根据阿伦尼乌斯方程绘制的不同温度（25℃至37℃）下牛磺胆酸盐摄取量的曲线呈线性。经乙炔雌二醇处理的肝细胞中，活化能增加了40%[17±4对23±4 kcal·mol⁻¹·(10⁶个细胞)⁻¹；P<0.05]，这与膜流动性降低一致。这些数据表明，在乙炔雌二醇诱导的胆汁淤积过程中，肝血窦区域的紊乱（可能是由乙炔雌二醇诱导的膜脂质组成改变所致）可能是一个重要的促成因素。
