Department of Pharmacology and Toxicology and James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky.
Department of Pharmacology and Toxicology and James Graham Brown Cancer Center, University of Louisville School of Medicine, Louisville, Kentucky
Drug Metab Dispos. 2017 Dec;45(12):1276-1281. doi: 10.1124/dmd.117.078543. Epub 2017 Oct 10.
Hydralazine is used in the treatment of essential hypertension and is under investigation for epigenetic therapy in the treatment of neoplastic and renal diseases. -acetyltransferase (NAT) 2 exhibits a common genetic polymorphism in human populations. After recombinant expression in yeast, human NAT2 exhibited an apparent Lineweaver-Burk constant () value (20.1 ± 8.8 M) for hydralazine over 20-fold lower than the apparent value (456 ± 57 M) for recombinant human NAT1 ( = 0.0016). The apparent value for recombinant human NAT1 (72.2 ± 17.9 nmol acetylated/min/mg protein) was significantly ( = 0.0245) lower than recombinant human NAT2 (153 ± 15 nmol acetylated/min/mg protein), reflecting 50-fold higher clearance for recombinant human NAT2. Hydralazine NAT activities exhibited a robust acetylator gene dose response in cryopreserved human hepatocytes both in vitro and in situ. Hydralazine NAT activities in vitro differed significantly with respect to NAT2 genotype at 1000 ( = 0.0319), 100 ( = 0.002), and 10 M hydralazine ( = 0.0029). Hydralazine NAT activities differed significantly ( < 0.001) among slow acetylator hepatocytes, (******). The in situ hydralazine -acetylation rates differed significantly with respect to NAT2 genotype after incubation with 10 ( = 0.002) or 100 M ( = 0.0015) hydralazine and were higher after incubation with 100 M (10-fold) than with 10 M (4.5-fold) hydralazine. Our results clearly document NAT2 genotype-dependent -acetylation of hydralazine in human hepatocytes, suggesting that hydralazine efficacy and safety could be improved by NAT2 genotype-dependent dosing strategies.
肼屈嗪用于治疗原发性高血压，并且正在研究其在治疗肿瘤和肾脏疾病中的表观遗传治疗作用。-乙酰基转移酶（NAT）2 在人类群体中表现出常见的遗传多态性。在酵母中重组表达后，人 NAT2 对肼屈嗪的表观 Lineweaver-Burk 常数（）值（20.1 ± 8.8 M）比重组人 NAT1 的表观值（456 ± 57 M）低 20 多倍（ = 0.0016）。重组人 NAT1 的表观值（72.2 ± 17.9 nmol 乙酰化/min/mg 蛋白）明显（ = 0.0245）低于重组人 NAT2（153 ± 15 nmol 乙酰化/min/mg 蛋白），反映重组人 NAT2 的清除率高 50 倍。肼屈嗪 NAT 活性在体外和原位冷冻保存的人肝细胞中均表现出强大的乙酰化基因剂量反应。在 1000（ = 0.0319）、100（ = 0.002）和 10 M 肼屈嗪（ = 0.0029）时，肼屈嗪 NAT 活性在体外显著（ ）因 NAT2 基因型而异。在孵育 10（ = 0.002）或 100 M（ = 0.0015）肼屈嗪后，原位肼屈嗪 -乙酰化率与 NAT2 基因型显著（）不同，并且孵育 100 M（10 倍）比孵育 10 M（4.5 倍）时更高。我们的结果清楚地证明了人肝细胞中肼屈嗪的 NAT2 基因型依赖性 -乙酰化，表明肼屈嗪的疗效和安全性可以通过 NAT2 基因型依赖性剂量策略来改善。
