Radioenzymatic microassay for simultaneous estimations of dopamine, norepinephrine, and epinephrine in plasma, urine, and tissues.

With this sensitive and specific radioenzymatic assay picogram quantities of norepinephrine, epinephrine, and dopamine can be simultaneously determined directly in plasma, urine, and tissue. We discuss in detail the steps that are critical for success of the assay, as well as the rationale behind the use of specific reagents. The assay is appropriate for use in any routine clinical chemistry laboratory. This assay is sensitive to approximately 1 pg of catecholamine. As compared with a commercially available method, this assay is significantly more economical and less time consuming.