Pleiotropic effect of LEC mutation: a rodent model of Wilson's disease.
Pleiotropic effect of LEC mutation: a rodent model of Wilson's disease.
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LEC 突变的多效性效应：威尔逊病的啮齿动物模型。
DOI：
10.1152/ajpgi.1994.266.5.g907
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Sternlieb,I
中科院分区：
文献类型：
--
作者：
Schilsky,ML;Stockert,RJ;Sternlieb,I
用~（67）Cu进行代谢研究，以确定Long-Evans Cinnamon（LEC）大鼠铜代谢中细胞缺陷的部位。与对照组（Vmax = 161 pmol.min-1.mg protein-1）相比，LEC原代肝细胞的铜摄取表观速率增加[最大速率（Vmax）= 259 pmol.min-1.mg protein-1];然而，Michaelis-Menten常数（Km）值相当（LEC和对照组分别为11.8和12.7 μ M）。LEC和对照肝细胞的铜流出量从0到15分钟是相似的，但在前者从15到60分钟减少。尽管LEC大鼠的肝脏铜含量与对照组相比显著升高（658 +/- 199 vs. 21.5 +/- 6.6微克/克干重），但LEC大鼠的胆汁铜浓度与对照组相比降低（0.187 vs. 1.39 +/- 0.66微克/毫升）。LEC肝匀浆的亚细胞分级显示约75%的铜存在于胞质溶胶中，从胞质溶胶到溶酶体或微粒体亚细胞组分的铜浓度梯度。LEC大鼠胆汁和肝微粒体和溶酶体馏分含有较小的分数的67铜静脉注射醋酸铜相比，对照组大鼠。然而，67 Cu标记的无唾液酸铜蓝蛋白（靶向溶酶体）给药后，LEC和对照组胆汁和溶酶体亚细胞组分中67 Cu的回收率相似。这种不一致性表明铜进入溶酶体可能存在缺陷，但溶酶体铜向胆汁的正常输送。基于这些发现，我们得出结论，LEC大鼠的突变改变铜转运在一个以上的细胞网站。
Metabolic studies with 67Cu were undertaken to identify the site of the cellular defect in copper metabolism in the Long-Evans Cinnamon (LEC) rat. The apparent rate of copper uptake by LEC primary hepatocytes was increased [maximal velocity (Vmax) = 259 pmol.min-1.mg protein-1] compared with controls (Vmax = 161 pmol.min-1.mg protein-1); however, Michaelis-Menten constant (Km) values were comparable (11.8 and 12.7 microM, LEC and control, respectively). Efflux of copper from LEC and control hepatocytes was similar from 0 to 15 min, but was reduced from 15 to 60 min in the former. Although hepatic copper contents were markedly elevated in LEC rats compared with controls (658 +/- 199 vs. 21.5 +/- 6.6 micrograms/g dry wt), biliary copper concentration was reduced in LEC rats compared with controls (0.187 vs. 1.39 +/- 0.66 microgram/ml). Subcellular fractionation of LEC liver homogenates revealed approximately 75% of copper to be present in cytosol, with gradients of copper concentration from cytosol to either lysosome or microsomal subcellular fractions. LEC rat bile and hepatic microsome and lysosome fractions contained smaller fractions of 67Cu administered intravenously as cupric acetate compared with control rats. However, recovery of 67Cu in bile and in lysosomal subcellular fractions were similar for LEC and controls following administration of 67Cu-labeled asialoceruloplasmin, which is targeted to lysosomes. This discordance suggests a possible defect in the entry of copper into lysosomes but normal delivery of lysosomal copper to bile. Based on these findings, we conclude that the mutation in LEC rats alters copper transport at more than one cellular site.