Urinary gamma-glutamyl transferase as an indicator of acute nephrotoxicity in rats.

A series of nephrotoxic compounds dissolved in 0.9% NaCl was given to groups of five male Wistar rats in a single i.p. injection. Mercuric acetate and mercuric trifluoroacetate at 1 mg Hg/kg induced a sharp increase in urinary gamma-glutamyl transferase (GGT) activity on day 1, followed by a decrease below control values on day 3. Sodium ethylmercurithiosalicylate induced a relatively small urinary GGT increase, explained by its low Hg-bioavailability. An increased urinary GGT activity was noted after treatment with the aminoglycoside antibiotics kanamycin, neomycin, paramomycin, and streptomycin (100 and 800 mg/kg), ammonium fluoride (18.5 and 37 mg/kg), potassium bichromate (7.5 and 30 mg/kg), sodium tetrathionate (62.5 and 125 mg/kg), and cis-diamminedichloroplatinum (2 and 4 mg/kg). This was lower than for the mercury compounds, but clearly different from the controls. The urinargy GGT increase was an acute phenomenon. It is concluded that the measurement of urinary GGT can be used as an indicator of acute nephrotoxicity.