The effect of dopamine intravenously injected in doses of 1 and 3 microg/kg/min on renal hemodynamics was studied in healthy individuals; the test followed a water load of 5 ml/kg. Glomerular infiltration rate and renal reserve were calculated from the blood and urine Cr concentration. The load of dopamine was found to be comparable with that of protein and amino acids. In most examinees, the renal reserve was preserved; however, it was absent in 3 persons, which needs further investigations. When used in doses of 1 and 3 microg/kg/min, dopamine showed the same potent stimulant effect; however, better tolerability was noted when the agent was injected in a dose of 1 microg/kg/min.