Steinberg P, Lafranconi W M, Wolf C R, Waxman D J, Oesch F, Friedberg T
Institute of Toxicology, University of Mainz, Federal Republic of Germany.
Mol Pharmacol. 1987 Oct;32(4):463-70.
To characterize the distribution and inducibility of drug metabolizing enzymes within different hepatic cell populations, the activities of aminopyrine N-demethylase, ethoxyresorufin O-deethylase, microsomal epoxide hydrolase and cytosolic glutathione transferase were measured in liver parenchymal, Kupffer, and endothelial cells isolated from untreated rats or rats pretreated with phenobarbital, 3-methylcholanthrene, or Aroclor 1254. Enzyme activities, measurable in all cases, were 2.3- to 5.7-fold higher in parenchymal cells than in Kupffer and endothelial cells. Phenobarbital increased aminopyrine N-demethylase, microsomal epoxide hydrolase, and cytosolic glutathione transferase activities, whereas 3-methylcholanthrene enhanced ethoxyresorufin O-deethylase, epoxide hydrolase, and glutathione transferase activities in the three cell populations. Aroclor 1254 consistently induced each of the enzyme activities in parenchymal, Kupffer, and endothelial cells. Western blot analyses revealed clear differences in the expression of proteins immunologically related to cytochrome P-450 PB-1, and glutathione transferases B and X in parenchymal cells compared with the corresponding Kupffer and endothelial cells. In contrast, only minor differences between the cell types were apparent in the expression of cytochromes P-450 PB-4, P-450 MC1a, P-450 MC1b and microsomal epoxide hydrolase. These studies establish that oxidative and postoxidative drug metabolizing enzymes are not restricted to parenchymal cells: similar but distinguishable complements of these enzymes are also found in Kupffer and endothelial cells.
为了表征不同肝细胞群体中药物代谢酶的分布和诱导性，我们测定了从未经处理的大鼠或经苯巴比妥、3-甲基胆蒽或多氯联苯混合物1254预处理的大鼠中分离出的肝实质细胞、库普弗细胞和内皮细胞中氨基比林N-脱甲基酶、乙氧基异吩恶唑酮O-脱乙基酶、微粒体环氧化物水解酶和胞质谷胱甘肽转移酶的活性。在所有情况下均可检测到酶活性，实质细胞中的酶活性比库普弗细胞和内皮细胞高2.3至5.7倍。苯巴比妥增加了氨基比林N-脱甲基酶、微粒体环氧化物水解酶和胞质谷胱甘肽转移酶的活性，而3-甲基胆蒽增强了三种细胞群体中乙氧基异吩恶唑酮O-脱乙基酶、环氧化物水解酶和谷胱甘肽转移酶的活性。多氯联苯混合物1254持续诱导实质细胞、库普弗细胞和内皮细胞中的每种酶活性。蛋白质印迹分析显示，与相应的库普弗细胞和内皮细胞相比，实质细胞中与细胞色素P-450 PB-1以及谷胱甘肽转移酶B和X免疫相关的蛋白质表达存在明显差异。相比之下，细胞色素P-450 PB-4、P-450 MC1a、P-450 MC1b和微粒体环氧化物水解酶的表达在细胞类型之间仅存在微小差异。这些研究表明，氧化和氧化后药物代谢酶并不局限于实质细胞：在库普弗细胞和内皮细胞中也发现了这些酶的类似但可区分的互补物。
