Plasma dopamine-beta-hydroxylase in uremia--increase in enzyme activity after renal transplantation.

Plasma dopamine-beta-hydroxylase in uremia. Plasma dopamine-beta-hydroxylase (DBH) activity was found to be low in 26 uremic patients when compared with 56 normal individuals (p less than 0.001). Hemodialysis caused only a slight increase in plasma DBH levels in the uremic group. In contrast, a group of kidney transplanted patients with a return of good renal function had DBH values similar to the normal group (p greater than 0.1). The mean plasma DBH activity in eight patients measured pre- and post-transplantation increased from 4.5 to 28 International Units/l (p less than 0.01). No evidence was found to indicate that the depressed levels of plasma DBH in uremia were secondary to genetic or enzyme inhibiting factors. It is suggested that low levels of DBH activity in patients with renal failure may be a consequence of altered sympathetic nervous activity which is known to occur in the uremic state.