Reliability of taurine concentrations measured in single urine samples obtained from dogs eight hours after eating

Objective-To evaluate the reliability of taurine concentrations measured in a single urine sample obtained from dogs 8 hours after eating, compared wi th taurine concentrations measured in 24-hour urine samples. Animals-18 healthy Beagles. Procedure-After emptying the urinary bladder by transurethral catheterizati on, dogs were fed a canned maintenance diet. Approximately 8 hours later, u rine, plasma, and serum samples were obtained for determination of fraction al urinary excretion of taurine and urine taurine-to-creatinine concentrati on ratios (U-taur:U-cr). Results were compared with 24-hour urinary taurine excretion rate. Results-Unbound and total fractional urinary taurine excretion correlated w ell with unbound and total 24-hour urinary taurine excretion. However, boun d fractional urinary taurine excretion correlated poorly with bound 24-hour urinary taurine excretion. Unbound and total U-taur:U-cr correlated well w ith unbound and total 24-hour urinary taurine excretion. However, bound U-t aur:U-cr correlated poorly with bound 24-hour urinary taurine excretion. Conclusion and Clinical Relevance-Fractional urinary excretion of unbound a nd total taurine, and unbound and total U-taur:U-cr are reliable indicators of 24-hour urinary unbound and total taurine excretion in healthy dogs. Ho wever, determination of 24-hour urinary taurine excretion is recommended fo r evaluating urinary bound taurine concentrations of dogs.