Plasma clearance of ⁵¹Cr‐EDTA as an estimator of glomerular filtration rate in conscious rats

A method is described whereby the plasma clearance of ⁵¹Cr‐EDTA is used to estimate the glomerular filtration rate (GFR) in conscious rats. EDTA clearance rates were calculated based on one and two exponential disappearance curves and compared in groups of animals studied under conditions of normal, high and low GFR. Like previously described related methodologies, this technique obviates the need for urine collections and marker infusions for GFR estimates. An important added advantage is that it provides the opportunity to study animals free of the effects of anesthetic, supine position and surgical stress.