Induction of a dose-related increase in sulfobromophthalein uptake velocity in freshly isolated rat hepatocytes by phenobarbital.
Induction of a dose-related increase in sulfobromophthalein uptake velocity in freshly isolated rat hepatocytes by phenobarbital.
复制标题
苯巴比妥诱导新鲜分离的大鼠肝细胞中磺溴酞摄取速度与剂量相关的增加。
DOI：
10.1002/hep.1840200441
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Berk,PD
中科院分区：
文献类型：
--
作者：
Potter,BJ;Ni,JZ;Wolfe,K;Stump,D;Berk,PD
为了确定苯巴比妥是否影响肝细胞胆红素/硫代溴眼蛋白的摄取机制，我们给体重175±25 gm的雄性Sprague - Dawley大鼠以1 ~ 75 mg/kg体重/天的剂量，连续7天。对照组给予等量生理盐水溶液。第8天，通过胶原酶灌注分离肝细胞，悬浮在不含白蛋白的Hanks溶液中，用高比活性（3 Ci/mmol） [35S]磺胺溴代眼蛋白孵育。磺胺溴代眼蛋白是我们实验室合成的，通过新型反相高压液相色谱法纯化。采用快速过滤法测定了磺胺溴代眼啡在浓度为1 ~ 50 μmol/L范围内的初始吸收率。用计算机分析方法测定了各剂量苯巴比妥对磺胺溴代眼啡的最大摄取速度和米切里斯常数。在对照研究中，最大摄食量和Michaelis常数分别为48.0±16.7 (mean±S.D.) μmol/ 50,000 cells/min和22±4 μmol/L。最大摄取速度随苯巴比妥剂量的对数线性增加（r = 0.98, p < 0.01），当剂量为3 mg/kg/d时，最大摄取速度的增加具有统计学意义。然而，当苯巴比妥剂量为50mg /kg/天或更低时，米切里斯常数基本不变。在早期的研究中，观察到的磺胺基眼啡最大摄取速度的最大增加（达到对照组的619%）明显大于UDP -葡萄糖醛基转移酶活性的最大增加（为对照组的200%）或免疫反应配体素浓度的最大增加（为对照组的260%），这表明对质膜运输机制有直接影响。(肝脏病学20:1078 1994;1085)。
To determine whether phenobarbital affects hepatocellular bilirubin/sulfobromophthalein uptake mechanism, we administered it to male Sprague‐Dawley rats, body weight 175 ± 25 gm, at doses of 1 to 75 mg/kg body wt/day for 7 days. Control rats were given an equivalent volume of physiological saline solution. On day 8, hepatocytes were isolated by means of collagenase perfusion, suspended in Hanks' solution without albumin and incubated with high specific activity (3 Ci/mmol) [35S]sulfobromophthalein, which was synthesized in our laboratory and purified by means of a new reverse‐phase high‐pressure liquid chromatography procedure. The initial uptake rate of sulfobromophthalein was determined at sulfobromophthalein concentrations of 1 to 50 μmol/L with a rapid filtration technique. The maximum uptake velocity and Michaelis constant for sulfobromophthalein uptake at each phenobarbital dose were determined by means of a computer analysis. In control studies, maximum uptake and Michaelis constant were 48.0 ± 16.7 (mean ± S.D.) pmol/50,000 cells/min and 22 ± 4 μmol/L, respectively. Maximum uptake velocity increased linearly with the log of the phenobarbital dose (r = 0.98, p < 0.01), the increase achieving statistical significance at a dose of 3 mg/kg/day. Michaelis constant, however, was essentially unchanged at phenobarbital doses of 50 mg/kg/day or less. The maximal observed increase in maximum uptake velocity of sulfobromophthalein (to 619% of control values) was appreciably greater than the maximal increase in UDP‐glucuronyltransferase activity (200% of control) or immunoreactive ligandin concentrations (260% of control) seen in earlier studies, suggesting a direct effect on the plasma membrane transport mechanism. (Hepatology 1994;20:1078–1085).