Retinol-binding protein in serum and urine of hyperthyroid cats before and after treatment with radioiodine.
BACKGROUND
Retinol-binding protein (RBP) is suggested as a clinically useful marker of renal function in cats.


OBJECTIVE
Serum and urinary RBP concentrations in hyperthyroid (HT) cats differ from those in healthy (H) cats; radioiodine ((131)I) treatment influences serum and urinary RBP concentrations in HT cats.


METHODS
Ten HT and 8 H cats.


METHODS
RBP concentration was evaluated in feline serum and urine samples from a prospective study.


RESULTS
There was a significant (P= .003) difference in the urinary RBP/creatinine (uRBP/c) ratios of H (-) and untreated HT (1.4 + or - 1.5 x 10(-2) microg/mg) cats. Serum total thyroxine concentration (1.8 + or - 1.9 microg/dL, 24 weeks) and uRBP/c (0.6 + or - 1.0 x 10(-2) microg/mg, 24 weeks) decreased significantly (P < .001) in HT cats at all time points after treatment with (131)I, and these variables were significantly correlated with one another (r= 0.42, P= .007). Serum RBP concentrations from HT cats (199 + or - 86 microg/L) did not differ significantly (P= .98) from those of H cats (174 + or - 60) and did not change after treatment with (131)I (182 + or - 124 microg/L, P= .80).


CONCLUSIONS
The presence of urinary RBP in HT cats is a potential marker of tubular dysfunction that is correlated to thyroid status, although it is independent of circulating RBP concentrations. The decreased uRBP/c combined with the absence of changes in serum RBP after treatment suggests that the suspected tubular dysfunction was partly reversible with treatment of (131)I.
van Hoek
I
I
Department of Medicine & Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium. ivanhoek@royal-canin.fr
Meyer
E
E
Duchateau
L
L
Peremans
K
K
Smets
P
P
Daminet
S
S
D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015153:Blotting, Western / Q000662:veterinary; D002371:Cat Diseases / Q000097:blood / Q000378:metabolism* / Q000532:radiotherapy* / Q000652:urine; D002415:Cats; D005260:Female; D006980:Hyperthyroidism / Q000097:blood / Q000532:radiotherapy / Q000652:urine / Q000662:veterinary*; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D016014:Linear Models; D008297:Male; D011446:Prospective Studies; D012177:Retinol-Binding Proteins / Q000378:metabolism* / Q000652:urine; D013974:Thyroxine / Q000097:blood
D015415:Biomarkers; D007457:Iodine Radioisotopes; D012177:Retinol-Binding Proteins; D013974:Thyroxine