Renal 131I-hippuran extraction in man: effects of dopamine.
OBJECTIVE
This study examined the 131I-hippuran extraction fraction during baseline renal blood flow rates and at high flow rates induced by dopamine.


METHODS
In 12 healthy subjects, arterial and renal venous sampling was used to measure the renal extraction of 131I-hippuran. Effective renal plasma flow values determined by the urinary clearance of 131I-hippuran were compared with renal plasma flow values corrected for incomplete extraction of 131I-hippuran.


RESULTS
Dopamine (3 micro g kg-1 min-1) decreased 131I-hippuran extraction from 75 +/- 4% at baseline to 62 +/- 6% (means +/- 95% confidence intervals, P < 0.001). Hence, the increase in renal plasma flow (85 +/- 23%) greatly exceeded the rise in effective renal plasma flow (51 +/- 15%, P < 0.002).


CONCLUSIONS
Dopamine induced increases in renal blood flow are largely under-estimated when measurements are not corrected for incomplete extraction of 131I-hippuran.
Hutchings
M
M
Department of Neuroanaesthesia, The Neuroscience Centre, Copenhagen University Hospital (Rigshospitalet), Denmark.
Hesse
B
B
Grønvall
J
J
Olsen
N V
NV
D000328:Adult; D004298:Dopamine / Q000494:pharmacology*; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D007465:Iodohippuric Acid / Q000493:pharmacokinetics*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D017596:Renal Plasma Flow, Effective / Q000502:physiology*
D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D004298:Dopamine