Plasma dopamine-beta-hydroxylase activity in normal young men: its responsiveness to manipulation of sodium balance and upright posture.
Plasma dopamine-beta-hydroxylase (DBH) activity was examined in nine healthy young adults. DBH activity at rest had a wide range, near 0 to 44 I.U./L. When sodium depletion was performed by dietary sodium restriction and diuretic, the activity was significantly increased. With dietary sodium loading, it was decreased. The change in DBH activity was significantly correlated with that in hematocrit. When subjects were erected, the enzyme activity was elevated in situations regardless of sodium balance. Blood pressure and pulse rate were changed by manipulation of sodium balance and postural change. However, the change in DBH activity did not correlate with them. Plasma renin activity (PRA) was determined concomitantly in the same plasma with DBH. The change in PRA had a direct correlation with that in DBH activity. Furthermore, the change in mean arterial pressure induced by infusion of angiotensin II analogue seemed to correlate with DBH activity change by sodium depletion. When the values of DBH activity in each individual were compared throughout the study, it was observed that the biggest variance in the activity of each individual was significantly correlated with the basal activity. In longitudinal study of individuals, plasma DBH activity could be a useful index for estimation of sympathetic activity.
D000328:Adult; D000804:Angiotensin II / Q000031:analogs & derivatives; D001794:Blood Pressure / Q000187:drug effects; D004039:Diet, Sodium-Restricted; D004299:Dopamine beta-Hydroxylase / Q000097:blood*; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D011187:Posture; D011674:Pulse / Q000187:drug effects; D012964:Sodium / Q000378:metabolism*
D000804:Angiotensin II; D005665:Furosemide; D012964:Sodium; D004299:Dopamine beta-Hydroxylase