THE CIRCADIAN VARIATION OF URINARY N-ACETYL-BETA-D-GLUCOSAMINIDASE AND GAMMA-GLUTAMYL-TRANSPEPTIDASE IN CLINICALLY HEALTHY CATS

The circadian variation of urinary N-acetyl-beta-D-glucosaminidase (NA G, EC 3.2.1.30) and gamma-glutamyl transpeptidase (gamma-GTP, EC 2.3.2 .2) was evaluated in cats. Urine and blood were collected at 4-hr inte rvals from adult cats (3 males, 9 females) weighing between 2.6 and 5. 0 kg. There was no circadian variation in the urine volume, creatinine clearance, creatinine excretion, NAG excretion or gamma-GTP excretion . The average NAG and gamma-GTP indices in the 4-hr urine were similar to those for the 24-hr urine. However, the variance for the 4-hr urin e samples was higher than that of 24-hr urine. In conclusion, although 4-hr urine samples can be used to estimate 24-hr urinary enzyme excre tion, short-term spot urine samples may cause increased variation in t he enzyme index.