Activities of Proximal Tubule Enzymes In Urine of Patients Treated With Gentamicin
The activities of the enzymes dominantly localized within the proximal tubules, such as alanine aminopeptidase (AAP), gamma-glutamyl transferase (GGT) and Nacetyl-beta-D-glucosaminidase (NAG), were measured in 12-h urine samples of patients suffering from Gram-negative infections and i.v. treated with gentamicin with the aim of determining the nephrotoxicity of this aminoglycoside antibiotic. The examined groups consisted of 3 - 10 years old children of both sexes, gentamicin-treated, and the control group, each including 30 patients. Urine samples were collected and analyzed five days before the gentamicin application and during the following 10 days of gentamicin treatment (a single i.v. injection per day in the dose of 2.5 mg/kg b.w.). Significant differences in the AAP and GGT activities expressed in U/mmol creatinine were observed between the gentamicin-treated group and the controls already on day 2 (p < 0.05) of the treatment, as well as in the activity of NAG on day 8 (p < 0.01) of the therapy. From these results it can be concluded that even standard gentamicin doses expressed nephrotoxic effects. Statistically significantly increased AAP and GGT activities in the gentamicin-treated group of children recorded already on the 2nd day of treatment demonstrate that these two enzymes represent extremely sensitive indicators of nephrotoxicity. On the other hand, statistically significantly increased NAG activity observed in the gentamicin-receiving group points to more severe gentamicin-provoked injuries of proximal tubules.