SINGLE-INJECTION INULIN-CLEARANCE - A SIMPLE METHOD FOR MEASURING GLOMERULAR-FILTRATION RATE IN DOGS

The glomerular filtration rates (GFR) of 93 dogs of different breeds w ith a broad range of bodyweight were determined using an inulin single -injection method. Fifty-two dogs were used as controls, 21 dogs had s uspected renal disease but serum creatinine in the normal range, and 2 0 dogs had elevated serum creatinine levels and a low urine specific g ravity due to renal disease. Inulin was injected intravenously at a do sage of 100 mg kg(-1) bodyweight or 3000 mg m(-2) body surface. Blood samples were taken before and three, 20, 40, 80 and 120 minutes after injection. The total clearance was calculated from the decrease in the serum concentration of inulin using a two-compartment model. The rang e of GFR values was 83.5-144.3 ml min(-1) m(-2) in control dogs, 60.2- 96.7 ml min(-1) m(-2) in dogs with suspected renal disease, 50.0-76.2 ml min(-1) m(-2) in dogs with suspected renal disease and polyuria/pol ydipsia, and 16.3-63.0 ml min(-1) m(-2) in dogs with azotaemic renal d isease. The study indicates that single-injection inulin clearance is a cheap and simple tool for GFR measurements in small animal practice.