Evaluation of methods for determining N-acetyl-beta-D-glucosaminidase in urine of rats without purification of urine samples.

N-Acetyl-beta-D-glucosaminidase (NAG) activities in urine of rats were measured with methods recommended as procedures without the pretreatment of urine sample. Four different derivatives [4-nitrophenyl; 3-cresolsulfonephthaleinyl; 3,3'-dichlorophenylsulfonephthaleinyl; 2-methoxy-4-(2-nitrovinyl)phenyl] of N-acetyl-beta-D-glucosaminide were compared for determination. The conventional test using the 4-nitrophenyl derivative showed the highest activities and was very well correlated with the other tests. The test using the 3,3'-dichlorophenylsulfonephthaleinyl substrate is most convenient and practical to determine NAG in small animals because it is, in contrast to the other three discontinuous (endpoint) tests, a continuous (kinetic) assay which can be easily adapted to clinical chemistry analyzers.