Glomerular filtration rate determined by measuring serum clearance of a single dose of inulin and serum symmetric dimethylarginine concentration in clinically normal cheetahs (Acinonyx jubatus)
OBJECTIVE To establish a reference interval for glomerular filtration rate (GFR) determined by measuring serum clearance of a single IV dose of inulin in clinically normal cheetahs (Acinonyx jubatus) and compare serum symmetric dimethylarginine (SDMA) concentration in cheetahs with GFR. ANIMALS 33 cheetahs housed at 3 institutions. PROCEDURES A single bolus of inulin (3,000 mg/m2) was administered IV, and 5 serial blood samples were collected and analyzed for serum inulin concentration with the anthrone technique. The GFR was estimated with a modified slope-intercept method for the slow component of the serum concentration-versus-time curve. Blood urea nitrogen and serum creatinine concentrations were measured in samples obtained immediately prior to inulin administration, and serum SDMA concentration was measured in stored samples. RESULTS Mean ± SD measured GFR was 1.58 ± 0.39 mL/min/kg, and the calculated reference interval was 0.84 to 2.37 mL/min/kg. There were significant negative correlations between GFR and serum creatinine concentration (r = −0.499), BUN concentration (r = −0.592), and age (r = −0.463). Serum SDMA concentration was not significantly correlated with GFR (r = 0.385), BUN concentration (r = −0.281), or serum creatinine concentration (r = 0.165). CONCLUSIONS AND CLINICAL RELEVANCE A reference interval for GFR in clinically normal cheetahs was obtained. Further evaluation of animals with renal disease is needed to determine whether measuring serum clearance of a single IV dose of inulin is a reliable diagnostic test for early detection of renal disease in cheetahs.
