Davidson D F, Grosset K, Grosset D
Department of Biochemistry, Crosshouse Hospital, Glasgow, UK.
Ann Clin Biochem. 2007 Jul;44(Pt 4):364-8. doi: 10.1258/000456307780945705.
L-dopa is an important antiparkinsonian drug. It is a precursor of dopamine and the other catecholamines. Potentially, administration of L-dopa could lead to increased urinary excretion of catecholamines and their metabolites to abnormal amounts. The current study aimed to determine these excretions in patients with Parkinson's disease (PD) receiving L-dopa compared with suitable controls. This is the first assessment of the effect of exogenous administration of L-dopa on urinary free metadrenalines.
Using one-way analysis of variance (ANOVA), urine catecholamines and metabolites, expressed as mmol per mole creatinine, were compared in: patients with PD who were receiving L-dopa; patients with PD but not receiving L-dopa; and patients without PD who were being investigated for the presence of phaechromocytoma but were found not to have the disease.
Significantly higher values for urinary dopamine, homovanillic acid, free normetadrenaline and free metadrenaline were found in patients with PD receiving L-dopa compared with the other two control groups. In all the patients with PD, these four analytes were significantly correlated with daily dose of L-dopa.
L-dopa therapy can result in production of false positives for urinary excretion of dopamine, homovanillic acid, free normetadrenaline or free metadrenaline and thereby decrease the diagnostic value of these measurements in identifying phaeochromocytoma and related tumours.
左旋多巴是一种重要的抗帕金森病药物。它是多巴胺和其他儿茶酚胺的前体。理论上，服用左旋多巴可能导致儿茶酚胺及其代谢产物的尿排泄量增加至异常水平。本研究旨在确定与合适对照组相比，接受左旋多巴治疗的帕金森病（PD）患者的这些排泄物情况。这是首次对外源性给予左旋多巴对尿游离变肾上腺素的影响进行评估。
采用单因素方差分析（ANOVA），比较以下三组以每摩尔肌酐毫摩尔数表示的尿儿茶酚胺及其代谢产物：接受左旋多巴治疗的PD患者；未接受左旋多巴治疗的PD患者；因疑似嗜铬细胞瘤接受检查但未患病的非PD患者。
与其他两个对照组相比，接受左旋多巴治疗的PD患者尿多巴胺、高香草酸、游离去甲变肾上腺素和游离变肾上腺素的值显著更高。在所有PD患者中，这四种分析物与左旋多巴的每日剂量显著相关。
左旋多巴治疗可导致尿多巴胺、高香草酸、游离去甲变肾上腺素或游离变肾上腺素排泄出现假阳性结果，从而降低这些测量在识别嗜铬细胞瘤及相关肿瘤时的诊断价值。
