URINARY CHOLINESTERASE ACTIVITY IS INCREASED IN INSULIN-DEPENDENT DIABETICS - FURTHER EVIDENCE OF DIABETIC TUBULAR DYSFUNCTION

We measured the cholinesterase activity in morning urines from 63 insu lin-dependent diabetics and 27 controls. The total esterase (TotE) act ivity (Ellman's method) has been divided into aliesterase (AliE), pseu docholinesterase and acetylcholinesterase by means of two inhibitors, eserine and quinidine. Diabetics were divided in 2 groups according to the urinary albumin/creatinine ratio (mg/mmol, < 2 in group 1, > 2 in group 2). The urinary cholinesterase behavior was correlated with tha t of a known tubular lysosomal hydrolase, N-acetyl-beta-D-glucosaminid ase (NAG). Compared to normals, in addition to a significant increase in urinary NAG in diabetics (in group 2 more than in group 1), TotE an d AliE were also significantly raised (+36% and 109% of the controls, in group 1 as much as in group 2).