Demonstration by in situ hybridization of the zonal modulation of rat liver cytochrome P-450b and P-450e gene expression after phenobarbital.
Demonstration by in situ hybridization of the zonal modulation of rat liver cytochrome P-450b and P-450e gene expression after phenobarbital.
复制标题
通过原位杂交证明苯巴比妥后大鼠肝细胞色素 P-450b 和 P-450e 基因表达的区域调节。
DOI：
10.1172/jci113645
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Gumucio,JJ
中科院分区：
文献类型：
--
作者：
Wojcik,E;Dvorak,C;Chianale,J;Traber,PG;Keren,D;Gumucio,JJ
构成肝功能的各种生理过程在肝腺泡内划分。调节这种肝细胞异质性的发展和维持的分子机制尚未确定。本研究的目的是确定细胞色素 P-450b,e 基因表达的转录或转录后区域调节是否与苯巴比妥 (PB) 给药后观察到的 P-450 蛋白的异质诱导有关。分别通过原位杂交和免疫荧光确定了通过诱导 P-450b、e mRNA 或蛋白质来响应 PB 的肝细胞在肝组织中的精确定位。通过对位于终末门静脉和肝小静脉之间的大约 20 个肝细胞的放射自显影照片进行定量评估证明，PB 在靠近肝小静脉（区域 2 和 3）的 12-15 个肝细胞中诱导 P-450b,e mRNA 达到六倍。相反，在终末门静脉（区域 1）周围的 4-6 个肝细胞中仅存在双重诱导。使用 MAb 进行的定量免疫荧光显示 PB 诱导的 P-450b,e 蛋白的腺泡分布与 mRNA 的分布相似。这种组合方法表明，最有可能的是，2区和3区肝细胞中细胞色素P-450b、e基因的转录率同时增加，而1区肝细胞中这些基因的激活或抑制相对缺乏，是造成PB给药后观察到的异质表型的原因。因此，肝腺泡肝细胞间基因表达的调节是实现肝细胞功能异质性的一种机制。在施用 PB 或对羟基苯巴比妥（PB 的主要肝脏代谢物）后研究细胞色素 P-450b,e 基因诱导的实验表明，参与诱导过程的物种是母体 PB 分子而不是对羟基苯巴比妥。
The various physiological processes that constitute liver function are compartmentalized within the hepatic acinus. The molecular mechanisms modulating the development and maintenance of this hepatocyte heterogeneity have not been defined. The objective of this study was to determine whether transcriptional or posttranscriptional zonal modulation of cytochromes P-450b,e gene expression was responsible for the heterogeneous induction of the P-450 proteins, which is observed after phenobarbital (PB) administration. The exact localization in liver tissue of hepatocytes responding to PB with induction of either P-450b,e mRNA or proteins was established by in situ hybridization and by immunofluorescence, respectively. As demonstrated by quantitative assessment of autoradiographs of approximately 20 hepatocytes located between a terminal portal venule and a hepatic venule, PB induced the P-450b,e mRNA up to sixfold in the 12-15 hepatocytes located closer to the hepatic venules (zones 2 and 3). In contrast, there was only a twofold induction in the 4-6 hepatocytes surrounding the terminal portal venules (zone 1). Quantitative immunofluorescence using an MAb showed that the acinar distribution of PB-induced P-450b,e proteins was similar to that of the mRNA. This combined approach indicated that, most likely, an increased rate of transcription of cytochromes P-450b,e genes in hepatocytes of zones 2 and 3 concomitantly, with a relative lack of activation, or repression, of these genes in hepatocytes of zone 1, were responsible for the heterogeneous phenotype observed after PB administration. Therefore, modulation of gene expression among hepatocytes of the liver acinus is one mechanism by which the functional heterogeneity of hepatocytes is attained. Experiments in which the induction of cytochromes P-450b,e genes was studied after administration of either PB or para-hydroxyphenobarbital, a main hepatic metabolite of PB, suggested that the species involved in the inductive process is the parent PB molecule rather than para-hydroxyphenobarbital.Images