Urinary gamma-glutamyl transferase activity in rats with nonsteroidal anti-inflammatory drug-induced nephrotoxicity

Excretion of urinary gamma-glutamyl transferase (GGT) was studied in rats following p.o. application of high doses (10 mg/kg/day) of indomethacin, diclofenac sodium or piroxicam for 28 days. Measurements of 24 h urinary GGT activity and urinary creatinine were carried out on 29th day. Histological examinations of kidneys were performed on day 29. The mean value for urinary GGT was found to be 0.77 +/- 0.05 U/mg creatinine (n = 16) in the control group. The mean activities in the treated groups were as follows: 1.30 +/- 0.15 U/mg creatinine (n = 17, indomethacin); 1.22 +/- 0.25 U/mg creatinine (n = 4, diclofenac); 1.54 +/- 0.39 U/mg creatinine (n = 5, piroxicam). The mean enzyme activities in indomethacin and piroxicam treated groups were significantly higher than in the control group (p < 0.02 and p < 0.03, respectively), while no significant difference has been found between the group treated with diclofenac and control group (p > 0.05). Histological examinations of renal tissues of indomethacin, piroxicam and diclofenac treated groups showed minimal glomerular abnormalities. Thus, determination of urinary GGT may be useful to investigate the nonsteroidal anti-inflammatory drugs (NSAIDs) related renal toxicity in rats.