Single-Injection Inulin Clearance for Routine Determination of Glomerular Filtration Rate in Cheetahs (Acinonyx jubatus)
A high prevalence of four unusual diseases has been seen among captive cheetahs from the United States and the Republic of South Africa (RSA).1,9 Of these four conditions, two are renal diseases. Renal disease is considered the leading cause of mortality in captive cheetahs.8 The diagnosis of renal disease in cheetahs is achieved, in most cases, once the kidneys have reached an end-stage. The presence of azotemia is the most common laboratory abnormality observed in cats with renal disease. When azotemia is present, at least 75% of the nephrons of the kidneys are non-functional already.4 At this point, treatment is unrewarding. Glomerular filtration rate (GFR) is considered a more sensitive test for the detection of early-stage renal disease.5 GFR is also considered to be the best single parameter for assessing overall renal function because GFR is directly related to functional renal mass.3 A simple technique for the assessment of GFR via the determination of inulin clearance from serum or plasma after a single intravenous injection has recently been described in domestic cats and dogs.2,6,7 The studies in domestic carnivores concluded that the inulin excretion test, using a single blood sample at 3 hours after the administration of intravenous inulin, is a valuable tool for the determination of GFR in these species. In summary, animals with suspected renal disease or confirmed renal disease had lower GFR values than control animals.6,7 Using this technique we determined the glomerular filtration rate on three populations of cheetah managed under different conditions. The determination of GFR in captive cheetahs offers the possibility of establishing baseline parameters that could potentially help in the diagnosis of renal disease in early stages.
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