EFFECTS OF NORADRENALINE AND DOPAMINE INFUSIONS ON ARACHIDONIC-ACID METABOLISM IN MAN

We infused noradrenaline (0.025 mu g/kg/min for 60 min, n=7) and dopam ine (3.0. mu g/kg/min for 60 min, n=6) into healthy male volunteers to study the effects of these catecholamines on in vivo thromboxane A(2) , prostacyclin and leukotriene E(4) production measured as urinary exc retions of 11-dehydro-thromboxane (TX) B-2, 2,3-dinor-6-keto-prostagla ndin (PG) F-1 alpha and leukotriene (LT) E(4), respectively. Plasma no radrenaline and dopamine concentrations were 2.9+/-0.3 and 233+/-17 nm ol/l at the end of the noradrenaline and dopamine infusions, respectiv ely. Noradrenaline decreased thromboxane production and increased leuk otriene production almost twofold. It had hardly any effect on prostac yclin production. Dopamine had no significant effects on any of the va riables, however it had a tendency to increase prostacyclin and leukot riene production. The results indicate that noradrenaline is a more im portant modulator of arachidonic acid metabolism than dopamine in vivo .