Abstract
We have developed a highly sensitive system of high-performance liquid chromatography (HPLC) consisting of an electrochemical detector and an automatic pretreatment device.
Using this system, basic studies on the mesurement of plasma free catecholamines (CA). i.e., noradrenaline (NA), adrenalin (A), and dopamine (DA) were carried out, their normal values were determined, and their clinical significance in various diseases such as hypertension was evaluated. The coefficient of variation (CV) for the simultaneous reproducibility of this method was 2.0-5.1%. The CV for day-to-day precision was 3.5-4.3%, and the recovery rates were 88-100%. A comparison of analysis of NA, A on this method with the HPLCfluorescence method (trihydoroxyindole method) shows that correlation for each are very high (correlation coefficients>0.9). The normal values obtained using this method (n=60) were (pg/ml): 160.1±70.5 (±SD) for NA, 30.1±15.2 for A, and 9.1±3.5 for DA. Loading tests in the standing position in patients with hypertension showed significant differences between NA, renin, and aldosteron values before loading and those after loading (p<0.05). Londing tests in other diseases also showed the usefulness of NA as a diagnostic index. This method is more sensitive than the conventional method and the limit concentration for detection (signal/noise=3) was considered to be 5pg/ml for DA. In addition, since no drug for deproteinization are used, free CA only can be measured without hydrolysis of conjugated CA. The handling and maintenance of the measurement system are also simple. This method seems to be appropriate for routine examinations of plasma Catecholamime levels.
