ObjectiveTo assess the thermogenic response of dopamine at three different infusion rates and to analyze its effects on various biochemical variables.DesignRandomized sequential experimental treatment bracketed by control periods.PatientsEight young healthy male volunteers with normal body weight (51 to 89 kg).InterventionsThree experimental periods during which dopamine was administered iv in a randomized order at rates of 2.5, 5, or 10 μg/kg·min with one preinfusion baseline and two recovery periods in between.Measurements and Main ResultsA significant (p< .01) increase in resting energy expenditure was observed in response to the two highest dopamine infusion rates (5 and 10 μg/kg·min), corresponding to 6% and 15% median increases, respectively, as compared with preinfusion values. At the lowest dopamine infusion rate, no variation in resting energy expenditure was observed. Dopamine induced a significant (p< .01) increase in hyperglycemia at all three infusion rates, and, at the highest infusion rate, dopamine induced a significant (p< .05) increase of plasma free fatty acid concentrations. Insulin plasma concentrations were significantly (p< .05 top< 0.1) increased at the three dopamine infusion rates.ConclusionsDopamine infusion produces a dose-dependent thermogenic effect and induces various metabolic actions in man.