CYTOCHROME-P450-DEPENDENT ARACHIDONIC-ACID METABOLISM IN HUMAN-KIDNEY
CYTOCHROME-P450-DEPENDENT ARACHIDONIC-ACID METABOLISM IN HUMAN-KIDNEY
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DOI：
10.1038/ki.1990.13
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发表时间：
1990-01-01
影响因子：
19.6
通讯作者：
ABRAHAM, NG
中科院分区：
文献类型：
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作者：
SCHWARTZMAN, ML;MARTASEK, P;ABRAHAM, NG
从几个死后的人肾皮质细胞色素P450依赖花生四烯酸代谢的特点。使用HPLC和GC/MS，四种细胞色素P450-花生四烯酸代谢产物被暂时但不明确地鉴定为环氧二十碳三烯酸（EET），二羟基二十碳三烯酸（DHT）和19-和20-羟基二十碳四烯酸，这表明两种主要的细胞色素P450酶，环氧合酶和w/w-1羟化酶的参与。这种代谢模式类似于在兔和大鼠kineys中发现的。这些代谢产物的形成依赖于NADPH的存在，并被NADPH-细胞色素P450（c）还原酶的IgG抑制。肾细胞色素P450环氧合酶的免疫学研究表明，制备的抗人肝细胞色素P450环氧合酶的抗体识别酶蛋白，并抑制酶活性的92%。相反，对照免疫球蛋白不抑制肾细胞色素P450环氧合酶。肾脏细胞色素P450环氧合酶的抗体抑制证明了肝脏和肾脏之间的两种酶蛋白的保守程度。抗月桂酸w/w-1羟化酶（P450 w）的抗体抑制w/w-1羟化酶产物19-和20-HETE的形成。在所有研究的皮质微粒体中观察到花生四烯酸代谢产物的相同定性模式。细胞色素P450依赖的花生四烯酸代谢存在个体间差异，活性范围为0.031 ~ 5.027 nmol花生四烯酸转化/mg蛋白/30 min，相差约1150倍。然而，当计算总细胞色素P450依赖的花生四烯酸代谢的比活性时，可以区分两个独立的组，花生四烯酸的高代谢者和低代谢者。细胞色素P450对花生四烯酸的低代谢物的范围为0.15至0.23 pmol花生四烯酸转化/pmol P450/min，与高代谢者的范围（1.38 - 1.91 pmol花生四烯酸转化/pmol P450/在所研究的其他细胞色素P450单加氧酶系统中也观察到花生四烯酸代谢的个体间差异，芳烃羟化酶和7-乙氧基试卤灵-O-脱乙基酶。细胞色素P450衍生的花生四烯酸代谢物具有广泛的生物活性，包括刺激肽激素释放、抑制和刺激Na+-K+-ATP酶、血管反应性和Ca++动员。我们认为细胞色素P450依赖的花生四烯酸代谢中观察到的个体间差异可能在某些个体发展为临床疾病（如原发性高血压）的易感性中发挥作用。
Cytochrome P450-dependent arachidonic acid metabolism in human kidney cortex from several postmortem subjects has been characterized. Using HPLC and GC/MS, four cytochrome P450-arachidonic acid metabolites were tentatively but not unequivocally identified as epoxyeicosatrienoic acid (EET), dihydroxyeicosatrienoic acid (DHT) and 19- and 20-hydroxyeicosatetraenoic acids, suggesting the involvement of two major cytochrome P450 enzymes, epoxygenase and w/w-1 hydroxylases. This pattern of metabolism was similar to that found in rabbit and rat kineys. The formation of these metabolites was dependent on the presence of NADPH and inhibited by IgG of NADPH-cytochrome P450 (c) reductase. Immunologic studies of renal cytochrome P450 epoxygenase demonstrated that antibodies prepared against human-purified hepatic cytochrome P450 epoxygenase recognized and enzyme protein and inhibited the enzyme activity by 92%. In contrast, control immunoglobulin did not inhibit renal cytochrome P450 epoxygenase. Antibody inhibition of renal cytochrome P450 epoxygenase demonstrated a degree of conservation of both enzyme proteins between liver and kidney. Antibodies against lauric acid w/w-1 hydroxylases (P450w) inhibited the formation of w/w-1 hydroxylase products, 19- and 20-HETEs. Identical qualitative patterns of arachidonic acid metabolites were observed in all cortical microsomes studied. Interindividual variations were observed in the cytochrome P450-dependent arachidonic acid metabolism, and the activities ranged from 0.031 to 5.027 nmol arachidonic acid converted/mg protein/30 min, which is about 1 150-fold difference. However, when the specific activities for total cytochrome P450-dependent arachidonic acid metabolism were calculated, two separate groups could be distinguished, high and low metabolizers of arachidonic acid. The range of the low metabolizer of arachidonic acid by cytochrome P450 was 0.15 to 0.23 pmol arachidonic acid converted/pmol P450/min, as compared to the range of the high metabolizer which was 1.38 to 1.91 pmol arachidonic acid converted/pmol P450/min. The interindividual variation observed with respect to arachidonic acid metabolism was also observed in other cytochrome P450 monooxygenase systems studied, aryl hydrocarbon hydroxylase and 7-ethoxyresorufin-O-deethylase. Arachidonate metabolites derived by cytochrome P450 have been shown to possess a wide range of biological activities; these include stimulation of peptide hormone release, inhibition and stimulation of Na+-K+-ATPase, vasoreactivity and mobilization of Ca++. We suggest that the interindividual variations observed in cytochrome P450-dependent arachidonic acid metabolism may play a role in the susceptibility of certain individuals to develop clinical disorders such as essential hypertension.