The effects of therapy for mild hypertension on circulating level of dopamine beta-hydroxylase.
Circulating dopamine beta-hydroxylase levels and norepinephrine excretion were measured in 76 mild hypertensive patients. Levels of dopamine beta-hydroxylase, norepinephrine excretion and blood pressure were obtained both before and after the initiation of therapy. Data from 20 patients exhibiting a diastolic blood pressure decrease of 10 mmHg or more were compared with data from 10 normotensive individuals. Changes in dopamine beta-hydroxylase levels were similar for the two groups and were not related to blood pressure changes. Intra-individual variation was small in both groups. There were no detectable functional relationships between diastolic pressure and urinary norepinephrine, norepinephrine and dopamine beta-hydroxylase or dopamine beta-hydroxylase and diastolic pressure. It dose not seem likely that dopamine beta-hydroxylase levels can replace urinary catecholamines as a commonly used index of sympathetic activity.