Radioactive chromium-ethylenediaminetetraacetic acid for determination of glomerular filtration rate in rabbits.
Simultaneous determination of the glomerular filtration rate was made by the insulin clearance technique and by analysis of the plasma disappearance curve of radioactive chromium-ethylenediaminetetraacetic acid (51Cr-EDTA) following an intravenous injection in 28 anaesthetized rabbits. In some rabbits, the renal function was reduced by previous surgery. The insulin clearances ranged from 2.7 to 17 ml/minute. By a double-exponential analysis of the plasma disappearance curve, the total plasma clearance of 51Cr-EDTA was found to exceed the inulin clearance by 12%. By the simpler slope-intercept analysis requiring only two blood samples, this value was 32%. The renal clearance of 51Cr-EDTA was 97% of inulin clearance. In nephrectomized rabbits, plasma clearance of 51Cr-EDTA was 0.7 ml/minute. At all levels of renal function, measurement of the plasma clearance rate of 51Cr-EDTA by the single injection technique allowed a fairly reliable estimate of the glomerular filtration rate.