Dopamine-induced dissociation between renal metabolic rate and sodium reabsorption

The stimulatory effect of dopamine on renal energy metabolism and its relationship to changes in tubular sodium reabsorption and plasma concentration of free fatty acids (FFA) were examined in anesthetized dogs. Dopamine infused intravenously at 25 mug/kg body wt-min for 30-60 min increased renal oxygen consumption (Rvo2) by 28 +/- 3%; glomerular filtration rate rose from 37 +/- 3 to 40 +/- 2 ml/min without significant changes in sodium excretion. Plasma FFA increased about 6 times. Total-body metabolic rate increased to 152 +/- 7% and fell to 119 +/- 5% of control after normalizing plasma FFA by beta-pyridylcarbinol; Rvo2 remained unchanged. Cortical and outer medullary heat accumulation rated increased to 137 +/- 6 and 133 +/- 10% after 1 h and to 163 +/- 18 and 179 +/- 26% of control after 2 h of dopamine infusion without further changes in sodium reabsorption. Furosemide reduced cortical and outer medullary metabolic rates as much as in control experiments (14 +/- 8 and 69 +/- 7%, respectively). Hence, dopamine exerts a renal calorigenic effect which cannot be accounted for by increased sodium reabsorption or attributed to increased supply of FFA.