Development of renal function test using dopamine and its utility in laboratory

尿中排泄的游离多巴胺来源于肾小管多巴胺，其在近端小管合成并调节尿钠排泄和利尿。尿中游离多巴胺来源于血浆多巴胺，其量可忽略不计。我们研究了尿游离多巴胺水平作为肾功能，特别是肾小管活动的标志物的有用性。我们确定了尿中游离多巴胺水平和一些已建立的肾功能标志物之间的相关性。尿游离多巴胺水平与血肌酐水平及尿α_1-和β_2-微球蛋白水平呈负相关。受试者工作特征（ROC）分析表明，尿游离多巴胺水平的敏感性和特异性优于其他已建立的肾脏参数上级。在肾脏疾病中，肾小管功能不全患者尿游离多巴胺水平显著低于肾小球功能不全患者。结果表明，尿游离多巴胺水平是肾功能的一个指标，是有用的评估肾损害，特别是肾小管功能障碍。

The free dopamine excreted in urine is derived from renal tubular dopamine, which is synthesized at the proximal tubules and regulates both natriuresis and diuresis. Urinary free dopamine derived from plasma dopamine is in negligible quantity. We investigated the usefulness of the urinary level of free dopamine as a marker of renal function, especially of tubular activity. We determined the correlations between the urinary level of free dopamine and a number of established markers of renal function. The urinary level of free dopamine was negatively correlated with the serum level of creatinine and the urinary levels of alpha_1-and beta_2-microglobulins. The receiver-operating characteristic (ROC) analysis indicated that urinary level of free dopamine is superior to other established renal parameters in sensitivity and specificity. In renal diseases, urinary level of free dopamine was significantly lower in patients with renal tubular dysfunction than in patients with glomerular dysfunction. Findings suggest that the urinary level of free dopamine is an index of renal function and is useful for evaluating renal impairments, especially renal tubular dysfunction.