Assessment of glomerular filtration rate in normal dog: analysis of the 51Cr-EDTA clearance and its relation to several endogenous parameters of glomerular filtration.

In 34 normal dogs the 51Cr-EDTA plasma clearance (C) according to the single injection technique was determined. The biexponential plasma disappearance curves were analysed according to a two compartment model. The results were compared with the plasma levels of creatinine and urea and with the endogenous creatinine clearance. In particular the dependence on body-weight (W) (range 8 to 57 kg) was established for several parameters. The dependence of C (ml per minute) on W (kg) could be described with both a linear function (C = 10 + 2.5 W) and a power function (C = 4.2 W0.88). The total distribution volume was equivalent to 19.6 per cent of W (range 12.1 to 33.5 per cent) whereas the rate constant lambda 0 (mean value 0.020 per minute, range 0.0115 to 0.0266 per minute) characterising the renal excretion did not depend on W. Good reproducibility (r = 0.92) of the C values was found in a test involving 13 dogs.