Urinary orotic acid-to-creatinine ratios in cats with hepatic lipidosis

Objective-To determine urinary orotic acid (OA) concentration and evaluate the urinary OA-to-creatinine ratio (OACR) in cats with hepatic lipidosis (H L). Animals-20 cats with Hi and 20 clinically normal cats. Procedure-Hepatic lipidosis was diagnosed on the basis of clinical signs, r esults of serum biochemical analyses, exclusion of other concurrent illness , and cytologic or histologic evaluation of liver biopsy specimens. Urine s amples were collected from each cat and frozen at -20 C until assayed. Urin e creatinine concentrations were determined, using an alkaline picrate meth od followed by spectrophotometric assay. Urine OA concentration was determi ned, using high-performance liquid chromatography. Minimum amount of detect able OA in feline urine was 1 mu g/ml. Because of small interfering peaks n ear the base of the OA peak, the minimum quantifiable concentration of OA w as determined to be 5 mu g/ml. Urinary OACR was compared in both groups of cats. Results-Differences in urinary OACR were not detected between clinically no rmal cats and cats with Hi, Peaks were not detected for urinary OA in any o f the 20 clinically normal cats. Of the 20 HL cats, 14 did not have detecta ble peaks for urinary OA. Of the 6 HL cats that had detectable urinary OA p eaks, 3 had values of < 5 mu g/ml. Conclusions-Apparently, OACR does not increase significantly in cats with H L. Clinical Relevance-Urinary OACR is not a useful diagnostic test for HL in c ats.