EXPERIMENTAL STUDIES COMPARING IOHEXOL AND CR-51-EDTA FOR GLOMERULAR-FILTRATION RATE MEASUREMENTS

The total plasma clearance as well as the renal clearance of iohexol w ere evaluated for determination of the glomerular filtration rate (GFR ) in 16 anesthetized pigs. The iohexol levels in urine and plasma were measured by X-ray fluorescence. The total plasma clearance of 1 and 4 ml/kg b.w. of iohexol 300 mg I/ml was compared to the simultaneously as well as nonsimultaneously calculated total plasma clearance of (51) CR-EDTA. The total plasma clearance of (51)CR-EDTA and of iohexol turn ed out to be equal and independent of the injected dose of iohexol. Th e injected dose did not have any effect on the renal clearance of iohe xol either. It is concluded that iohexol and (51)CR-EDTA are similar a s marker substances for determination of the GFR.