Effect of castration on urinary N-acetyl-beta-D-glucosaminidase levels in male beagles.

Urinary N-acetyl-beta-D-glucosaminidase (NAG), a sensitive marker for renal damage, was much higher in male beagles than in females. The daily output of NAG into urine in male beagles was almost three times that in females. Following bilateral vasectomy or castration, marked decreases occurred in urinary NAG output. These results led to the conclusion that the high urinary NAG output in male beagles is largely due to an admixture of secreted fluid from the gonadal system in the bladder. Thus, when using beagles for nephrotoxicity studies with NAG as a parameter, females are preferable.