Department of Toxicology, University of Würzburg, 9 Versbacher St., D-97078 Würzburg, Germany.
J Chromatogr B Analyt Technol Biomed Life Sci. 2010 Jan 1;878(1):97-101. doi: 10.1016/j.jchromb.2009.11.023.
Drug-drug and food-drug interactions are often due to an inhibition or induction of drug-metabolizing cytochrome P450 (CYP) enzymes and may result in non-response or adverse reactions. Hence, phenotypic biomarkers of CYP activity appear as useful tools for individualized pharmacotherapy. The metabolic ratio (MR) of the concentration of 6beta-hydroxycortisol (6beta-OHC) to cortisol (MR 6beta-OHC/cortisol) in human urine had been proposed as an endogenous marker for CYP3A activity. Here, we report on the improvement of published LC-MS/MS methods for the simultaneous quantification of cortisol and 6beta-OHC, using on-line sample cleanup by column switching and isotope-labeled analogues as internal standards. [(2)H(2)]6beta-OHC was prepared by incubation of human recombinant CYP3A4 with commercially available [(2)H(2)]cortisol. Analytical sensitivity could be increased about 10-fold. The first morning urine of 69 female and 27 male healthy volunteers was analyzed for cortisol and 6beta-OHC. Concentrations ranged from 1.0 to 142 and 24 to 670ng/mL, respectively. Individual MR 6beta-OHC/cortisol varied more than 20-fold and we were able to show for the first time for a Caucasian population significantly higher MR values in females as compared to males. This non-invasive biomarker for CYP3A activity lends itself for the study of genetic differences as well as enzyme induction or inhibition in the clinical setting without the need of using a probe drug.
药物-药物和食物-药物相互作用通常是由于药物代谢细胞色素 P450（CYP）酶的抑制或诱导，可能导致无反应或不良反应。因此，CYP 活性的表型生物标志物似乎是个体化药物治疗的有用工具。人尿中 6β-羟基皮质醇（6β-OHC）与皮质醇的浓度之比（MR 6β-OHC/皮质醇）曾被提议作为 CYP3A 活性的内源性标志物。在这里，我们报告了改进的 LC-MS/MS 方法，用于同时定量分析皮质醇和 6β-OHC，使用在线柱切换进行样品净化，并使用同位素标记的类似物作为内标。[(2)H(2)]6β-OHC 是通过用市售的[(2)H(2)]皮质醇孵育人重组 CYP3A4 制备的。分析灵敏度可提高约 10 倍。分析了 69 名女性和 27 名男性健康志愿者的晨尿中的皮质醇和 6β-OHC。浓度范围分别为 1.0 至 142 和 24 至 670ng/mL。个体 MR 6β-OHC/皮质醇的变化超过 20 倍，我们首次证明，与男性相比，女性的 MR 值明显更高。这种用于 CYP3A 活性的非侵入性生物标志物可用于研究遗传差异以及在临床环境中诱导或抑制酶，而无需使用探针药物。
