Armando I, Grossman E, Hoffman A, Goldstein D S
Clinical Neuroscience Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.
J Chromatogr. 1991 Jul 17;568(1):45-54. doi: 10.1016/0378-4347(91)80339-e.
The present report describes a method using column liquid chromatography with electrochemical detection for assaying concentrations of 3-O-methyldopa in urine and plasma. The technique combines a one-step sample preparation scheme with post-column flow-through electrodes in series, allowing adequate chromatographic separation of 3-O-methyldopa from other endogenous substances in urine. The validity of the method was confirmed by markedly decreased urinary 3-O-methyldopa levels after administration of an inhibitor of catechol-O-methyltransferase to rats, radioactivity in chromatographic fractions corresponding to 3-O-methyldopa in urine of rats undergoing infusion of [3H]-L-DOPA, and correlations between excretion rates of 3-O-methyldopa and catechols in humans. In healthy humans, urinary excretion of 3-O-methyldopa averaged 974 +/- 707 (S.D.) nmol per day, and plasma levels of 3-O-methyldopa averaged 89 +/- 32 nmol/l. The method should be useful in studies about the metabolism of endogenous and exogenous DOPA.
本报告描述了一种使用柱液相色谱结合电化学检测法来测定尿液和血浆中3 - O - 甲基多巴浓度的方法。该技术将一步样品制备方案与串联的柱后流通电极相结合，可使尿液中的3 - O - 甲基多巴与其他内源性物质实现充分的色谱分离。给大鼠注射儿茶酚 - O - 甲基转移酶抑制剂后，尿中3 - O - 甲基多巴水平显著降低；给大鼠输注[3H] - L - 多巴后，尿中与3 - O - 甲基多巴相对应的色谱馏分中的放射性；以及人体中3 - O - 甲基多巴排泄率与儿茶酚之间的相关性，均证实了该方法的有效性。在健康人体中，3 - O - 甲基多巴的尿排泄量平均为每天974±707（标准差）nmol，血浆水平平均为89±32 nmol/L。该方法在内源性和外源性多巴代谢研究中应具有实用价值。
