Langouët S, Morel F, Meyer D J, Fardel O, Corcos L, Ketterer B, Guillouzo A
INSERM U49, Unité de Recherches Hépatologiques, Hôpital Pontchaillou, Rennes, France.
Hepatology. 1996 Apr;23(4):881-7. doi: 10.1002/hep.510230432.
Recently, we used human hepatocytes in primary culture to study the effects of inducers of glutathione-S-transferases (GSTs) in the expectation that information obtained can be used to predict the value of particular inducers for use in the chemoprevention of cancer and other toxicities. However, in vitro human studies cannot readily be confirmed by studies in vivo. This problem does not arise in experimental animals. In the current studies, the response of male rat hepatocytes in primary culture to the following inducers of GST isoenzymes has been determined: 3-methylcholanthrene (MC); phenobarbital (PB); 1,2-dithiole-3-thione and its 5-(2-pyrazinyl)-4-methyl derivative, oltipraz (OPZ), and the results have been compared with induction obtained in livers of MC- and OPZ-treated rats. Each type of inducer was found to elicit a different response. In vitro, phenobarbital increased messenger RNA (mRNA) levels of subunits 1b and 3 after 12 and 72 hours, respectively; MC had a rapid effect on GST alpha class mRNAs (bringing about increase after only 2 hours of treatment), increased subunit 7 mRNA slightly, and had no effect on mu class mRNAs; dithiolethiones induced both subunit lb and 7 mRNAs after 4 hours and, to a much lower extent, subunit 3 mRNA after 72 hours. In vivo, MC induced significantly both subunit lb and 7 mRNAs whereas OPZ increased significantly subunits lb, 3 and 7 mRNA levels, and to a lower extent those of subunit 2, after 3 days and beyond to at least 5 days of treatment. Results obtained in mRNA studies were confirmed by high-pressure liquid chromatography (HPLC) analysis of GST subunits. HPLC also showed an induction of subunit 10 at the protein level of which the mRNA was not analyzed. Our results show that rat hepatocytes in primary culture prove to be a good model for the effect of inducers on both the expression of GST mRNA and protein levels in the rat liver in vivo. The demonstration of this good correlation in the rat with respect to increases gives support for the use of human hepatocytes for predictive studies of chemoprotection in human pharmacology.
最近，我们利用原代培养的人肝细胞来研究谷胱甘肽-S-转移酶（GSTs）诱导剂的作用，期望所获得的信息能够用于预测特定诱导剂在癌症化学预防及其他毒性预防中的价值。然而，体外人体研究结果难以通过体内研究得到证实。而在实验动物中则不存在这个问题。在当前的研究中，已确定原代培养的雄性大鼠肝细胞对以下GST同工酶诱导剂的反应：3-甲基胆蒽（MC）；苯巴比妥（PB）；1,2-二硫杂环戊烯-3-硫酮及其5-（2-吡嗪基）-4-甲基衍生物奥替普拉（OPZ），并将结果与MC和OPZ处理大鼠肝脏中的诱导情况进行了比较。发现每种诱导剂都会引发不同的反应。在体外，苯巴比妥分别在12小时和72小时后增加了亚基1b和3的信使核糖核酸（mRNA）水平；MC对GSTα类mRNA有快速作用（仅处理2小时后就导致增加），使亚基7 mRNA略有增加，而对μ类mRNA无影响；二硫杂环戊烯酮在4小时后诱导了亚基1b和7 mRNA，在72小时后诱导亚基3 mRNA的程度则低得多。在体内，MC在处理3天后及至少至5天显著诱导了亚基1b和7 mRNA，而OPZ显著增加了亚基1b、3和7 mRNA水平，对亚基2 mRNA水平的增加程度较低。mRNA研究结果通过GST亚基的高压液相色谱（HPLC）分析得到了证实。HPLC还显示在蛋白质水平上诱导了亚基10，而未对其mRNA进行分析。我们的结果表明，原代培养的大鼠肝细胞被证明是诱导剂对大鼠肝脏中GST mRNA表达和蛋白质水平影响的良好模型。在大鼠中关于增加情况的这种良好相关性的证明，为在人类药理学中使用人肝细胞进行化学保护预测研究提供了支持。
