[Renal effects of dopamine in healthy adults with special reference to the excretion of phosphate and calcium].

Abstract

The intravenous application of 4 micrograms/kg/min dopamine (DA) over 3 h in 11 healthy volunteers resulted in an increase in inulin clearance and urine volume by about 10%, renal excretion of sodium and calcium being increased by DA by a factor of 5. We found a strong linear correlation between changes of renal excretion of sodium and calcium under DA (r = 0,90). The concentration of ionized calcium in whole blood was absolutely stable under DA in the range of 1.25 to 1.27 mmol/l. The application of the catecholamine also resulted in a significant reduction of plasma volume by a mean of about 10% and in a nonsignificant reduction of intravascular protein mass by 8%. The phosphaturic effect of DA was weak and unpredictable. We suppose that in the intact organism the pharmacologic effect of dopamine on the tubular handling of phosphate which seems to be experimentally proven, may be masked by other mechanisms with an antiphosphaturic action such as increased levels of growth hormone and/or insulin.