La gamma-glutamyl transferase urinaire en toxicologie renale chez le rat. Bases de son utilisation-interet lors de nephrite aigue mercurielle

Summary Kidney specificity and toxicological value of urine gamma-glutamyl transferase (GGT) have been investigated in the rat. At first, it was checked in 30 Cobs rats that urinary GGT originates only from kidney and not from other parts of the genito-urinary tract. Conditions of urine collection and of activity measurement were studied: (1) urine GGT was stable at room temperature and at +4°C, but was rapidly inactivated by freezing, (2) GGT activity in urine was measured without prior dialysis after a 5 mn centrifugation at 3000 g and a dilution in saline (1/10, v/v). Reference values in Cobs rats weighing 250–350 g were: 381 ± 139 U/1 or 3.73 ± 1.43 U/24 h for males and 205 ± 79 U/1 or 1.89 ± 0.57 U/24 h for females (P In acute mercuric nephropathy resulting from single injection of 0, 0.25, 0.50, 1.0, 1.5 mg Hg/kg (HgCl 2 , i.p.), GGT activity in urine was compared with the following parameters: volume, sodium, potassium, chloride, urea, creatinine and alkaline phosphatase (PAL). Urine GGT was rapidly and intensively increased, more than PAL and volume, whereas the other parameters are lowered. More sensitive than kidney function tests, as sensitive as histology but performable in vivo, as specific as other urine enzymes but easier to measure without prior dialysis of urines, urine gamma-glutamyl transferase is a very good test for kidney tubular lesion.