Reference Values for Plasma Catechols

Objectives: Plasma levels of catechols have distinct meanings in terms of indicating functions of endogenous catecholamine systems. This Protocol is designed to enable ongoing quality assurance of diagnostic and research assays of catechols and their metabolites and to identify possible influences of demographic and anthropometric factors, dietary constituents, and conditions of sampling on reference values. Study Populations: The study population is healthy volunteers and people who are obese or have untreated hypertension. Design: Arm venous blood is drawn via an indwelling i.v. catheter from healthy volunteers across demographic and anthropometric spectra (age, gender, skin color, ethnicity, body mass, adiposity), to obtain quality control plasma and establish reference values for plasma levels of catechols and their metabolites. Non-invasive physiological measures are obtained concurrently. Levels of catechols and their metabolites are related to results of common clinical pathology tests. Subgroups of subjects are tested more than once, to assess dietary influences (cereal with milk, coffee) and conditions of sampling (temperature at the skin). Outcome Measures: The main non-experimental outcome is an ongoing pool of quality control plasma. The main experimental outcome measures are plasma concentrations of catechols and their metabolites, non-invasive physiological measures, and results of common clinical pathology tests. Subject groups are compared with respect to the above demographic and anthropometric factors. Effects of the experimental manipulations are assessed within subjects