Effects of administration of fluids and diuretics on glomerular filtration rate, renal blood flow, and urine output in healthy awake cats.
OBJECTIVE
To determine effects of commonly used diuretic treatments on glomerular filtration rate (GFR), renal blood flow (RBF), and urine output (UO) and compare 2 methods of GFR measurement in healthy awake cats.


METHODS
8 healthy cats.


METHODS
In a randomized crossover design, cats were randomly allocated to 4 groups: control; IV administration of fluids; IV administration of fluids and mannitol; and IV administration of fluids, dopamine, and furosemide. Inulin and para-aminohippuric acid were used for determination of plasma clearance for GFR and RBF, respectively. Plasma clearance of technetium-Tc-99m-diethylenetriaminepentacetic acid (99mTc-DTPA) was also used for GFR determination.


RESULTS
Furosemide-dopamine induced the largest UO, compared with other groups. Both mannitol and fluid therapy increased RBF, compared with the control group. Mannitol, and not fluid therapy, increased RBF, compared with furosemide-dopamine. There were significant differences in GFR values calculated from 99mTc-DTPA and inulin clearances between the 2 groups. In all groups, use of 99mTc-DTPA caused underestimation of GFR, compared with use of inulin.


CONCLUSIONS
In healthy awake cats, administration of furosemide-dopamine did not increase GFR or RBF despite increased UO. Fluid therapy and fluid therapy plus mannitol improved RBF. Determination of GFR by use of 99mTc-DTPA cannot always be substituted for inulin clearance when accurate measurement is required.
Department of Clinical Sciences, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Jennifer M
JM
McClellan
Richard E
RE
Goldstein
Hollis N
HN
Erb
Ned L
NL
Dykes
Larry D
LD
Cowgill
D000818:Animals; D002415:Cats / Q000502:physiology*; D004231:Diuresis / Q000187:drug effects / Q000502:physiology*; D004232:Diuretics / Q000494:pharmacology*; D005260:Female; D005440:Fluid Therapy; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000662:veterinary*; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D012079:Renal Circulation / Q000187:drug effects*; D014851:Wakefulness; D014882:Water-Electrolyte Balance
D004232:Diuretics