Regional hemodynamic effects of dopamine in the unanesthetized primate: Failure to alter flow-dependent hepatic drug clearance

The effects of dopamine on regional blood flow and hepatic drug clearance were determined in the unanesthesized monkey, using the radioactive microsphere technique and d-propranolol as a model drug with flow-dependent hepatic clearance. Dopamine at doses of 1 μg and 10 μg/kg/min caused little change in systemic hemodynamics but a large decrease in renal vascular resistence (−33% at high dose) and increase in renal blood flow (+40% at high dose). Blood flow to the liver was unchanged in the group and the clearance of d-propranolol was not consistently altered by dopamine. These data show that the major vascular bed affected by dopamine is in the kidney with little effect on splanchnic or hepatic circulations. That an agent to increase hepatic blood flow would be useful to increase the clearance of drugs with flow-dependent kinetics remains a distinct possibility.