Urinary excretion of catecholamines during dopamine infusion in man

This study was designed to evaluate the changes of endogenous catecholamine secretions in association with dopamine infusion (6.0 ± 1.9 μg/kg/min. mean ± S.D.) in man. In 18 patients undergoing gynecological abdominal surgery, epidural anesthesia combined with light general anesthesia was performed to suppress the physical and mental stress during surgery. Eleven of them were given dopamine during the operation (dopamine group) and the other 7 patients were not given dopamine (control group). Urine samples were collected before and during the operations, and the concentrations of dopamine, norepinephrine and epinephrine per 1 mg of creatinine were measured by high performance liquid chromatography using the native fluorescence detection method. In the dopamine group, norepinephrine excretion during the operations increased on average 66% compared with the preoperative value (p < 0.01). In contrast, in the control group, both norepinephrine and epinephrine excretion were unchanged. These results suggest that exogenous dopamine increases the plasma level of norepinephrine in man.