DECREASED SERUM DOPAMINE-BETA-HYDROXYLASE IN HYPERTHYROIDISM

ABSTRACT

In 21 patients with hyperthyroidism, the mean serum dopamine-betahydroxylase (DBH) activity was 19 I.U. compared to 40 I.U. in 41 normal subjects (p < .005). During therapy for hyperthyroidism in 6 of the patients, the mean DBH increased from 22 to 41. The finding of a low DBH in hyperthyroidism and the subsequent rise in DBH during treatment provides independent evidence that sympathetic nervous activity is decreased in hyperthyroidism.