An association between the lysosomal enzyme NAG and urinary free cortisol and platelet imipramine binding.

Urinary levels of the lysosomal enzyme N-acetyl-beta-glucosaminidase (NAG) were significantly correlated to levels of 24-hour urinary free cortisol in a group of panic disordered patients. In a separate study of healthy controls NAG levels showed a trend toward association with platelet imipramine binding density. A hypothesis is proposed that NAG levels may be proportional to the density of postsynaptic serotonin receptors.