Involvement of CYP3A in the metabolism of eplerenone in humans and dogs: Differential metabolism by CYP3A4 and CYP3A5
Involvement of CYP3A in the metabolism of eplerenone in humans and dogs: Differential metabolism by CYP3A4 and CYP3A5
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DOI：
10.1124/dmd.30.12.1344
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发表时间：
2002-12-01
影响因子：
3.9
通讯作者：
Zhang, LM
中科院分区：
文献类型：
--
作者：
Cook, CS;Berry, LM;Zhang, LM
本文报道了依普利酮（EP）在人体和犬体内的主要代谢产物及其主要氧化代谢产物细胞色素P450（P450）同工酶的体外研究。EP通过cDNA表达的人CYP 3A 4和犬CYP 3A 12代谢，但仅通过人CYP 3A 5代谢最低。在人微粒体中，CYP 3A选择性抑制剂酮康唑、三乙酰竹桃霉素和6 '，7'-二羟基香柠檬酸，各浓度为10 μ M，对总代谢的抑制率为83 - 95%，而对其他P450同工酶选择性抑制剂的抑制率最低。在犬肝微粒体中，CYP 3A选择性抑制剂的抑制百分比为53 - 76%。单克隆抗CYP 3A 4抗体可抑制EP代谢84%，而其他单克隆抗体的影响极小。人肝微粒体中6 β-羟基和21-羟基代谢产物的形成与CYP 3A选择性美沙芬N-去甲基化和睾酮6 β-羟基化活性相关性最好。EP在30、100和300 μ M浓度下仅中度抑制人肝微粒体中的CYP 3A（睾酮6 β-羟化酶）活性，抑制率分别为23%、34%和45%。对于人微粒体，6 β-羟基化和21-羟基化的Vmax和Km分别为0.973 nmol/min/mg和217 μ M，以及0.143 nmol/min/mg和211 μ M。根据总体外EP代谢计算的人肝脏清除率为2.30 ml/min/kg，与体内数据一致。总之，EP的6 β-和21-羟基化主要由人的CYP 3A 4和犬的CYP 3A 12催化。此外，EP不太可能大幅抑制经CYP 3A 4或其他P450亚型代谢的其他药物的代谢。
In vitro studies were conducted to identify the major metabolites of eplerenone (EP) and the cytochrome P450 ( P450) isozymes involved in its primary oxidative metabolism in humans and dogs The major in vitro metabolites were identified as 6beta-hydroxy EP and 21-hydroxy EP in both humans and dogs. EP was metabolized by cDNA-expressed human CYP3A4 and dog CYP3A12 but only minimally by human CYP3A5. In human microsomes, inhibition of total metabolism by the CYP3A-selective inhibitors ketoconazole, troleandomycin, and 6',7'- dihydroxybergamottin, each at 10 muM concentration, was 83 to 95%, whereas inhibition with inhibitors selective for other P450 isozymes was minimal. In dog liver microsomes, the percentages of inhibition were 53 to 76% with the CYP3A-selective inhibitors. A monoclonal anti-CYP3A4 antibody inhibited EP metabolism by 84%, whereas other monoclonal antibodies had minimal effects. The formation of 6beta-hydroxy and 21-hydroxy metabolites in human liver microsomes was best correlated with CYP3A-selective dextromethorphan N-demethylation and testosterone 6beta-hydroxylation activities. EP moderately inhibited only CYP3A (testosterone 6beta-hydroxylase) activity in human liver microsomes by 23, 34 and 45% at concentrations of 30, 100, and 300 muM, respectively. With human microsomes, the V-max and K-m for 6beta-hydroxylation and 21-hydroxylation were 0.973 nmol/min/mg and 217 muM, and 0.143 nmol/min/mg and 211 muM, respectively. The human hepatic clearance calculated from total in vitro EP metabolism was 2.30 ml/min/kg, which agrees with in vivo data. In conclusion, 6beta- and 21-hydroxylation of EP is primarily catalyzed by CYP3A4 in humans and CYP3A12 in dogs. Also, it is unlikely that EP would substantially inhibit the metabolism of other drugs that are metabolized by CYP3A4 or other P450 isoforms.