Serum dopamine beta-hydroxylase in cardiovascular diseases.

Dopamine-beta-hydroxylase (DBH), the enzyme responsible for the biosynthesis of norepinephrine from dopamine was assayed in the blood serum of 23 normal adults, 16 patients with congestive heart failure, 19 patients with asymptomatic ischemic heart disease, 4 patients with angina pectoris at rest, 15 patients with essential hypertension, 8 patients with essential hypotension, 5 patients with neurocirculatory asthenia, and 9 normal adults before and after the exercise test. The serum DBH activity varied within a wide range in the control population. The DBH activity increased about 16% after the exercise stress. A tendency to increase DBH activity was shown in the patients with congestive heart failure. There was no significant difference between asymptomatic ischemic heart disease, essential hypertension and normal controls. A lower value was observed in the patients of angina pectoris at rest, while a higher DBH activity was demonstrated in the patients with essential hypotension. There was no significant difference between the neurocirculatory asthenia group and the normal control group.