Serum dopamine-beta-hydroxylase activity and blood pressure

The purpose of the studies reviewed here was to investigate the role of inheritance in the regulation of human serum dopamine-beta-hydroxylase (DBH) activity. DBH is a catecholamine biosynthetic enzyme that is localized to catecholamine-containing vesicles, is released with catecholamines from sympathetic nerves and the adrenal medulla, and is found in serum. It has been suggested that serum DBH activity might be a useful and convenient measure of sympathetic nervous system function. DBH activity was measured in blood from large, randomly selected populations of children, adolescents, and adults and in blood of relatives of children with very low serum DBH activity (less than 50 units). The results of sibship and pedigree analyses of data from families of probands with very low enzyme activity were compatible with autosomal-recessive inheritance of very low serum DBH activity. In addition, the results of studies of immunoprecipitable serum DBH were compatible with a genetically mediated decrease in the quantity of DBH protein in the blood of subjects with this allele. No significant correlation of serum DBH activity with either systolic or diastolic blood pressure was found in a large, randomly selected population of children.