URINARY-EXCRETION OF GLUTAMINE TRANSAMINASE-K AS AN EARLY INDEX OF MERCURIC CHLORIDE-INDUCED NEPHROTOXICITY

The possibility that urinary glutamine transaminase K activity might b e a marker of a proximal tubule segment-specific response to mercuric chloride was investigated in male rats after a single i.p. injection i n time-course and dose-response experiments. Urinary total proteins an d angiotensin converting enzyme activity were determined simultaneousl y. Urinary indices showed an early increase (within 5 h of treatment) of total proteins and angiotensin converting enzyme, whereas glutamine transaminase K increased 10 h after treatment. The peak of all these indices was observed 24 h after mercuric chloride injection. The lowes t dose that induced a significant increase in proteins and enzymes was 0.25 mg kg(-1); in addition, a dose-response effect was observed. Glu tamine transaminase K appeared to be an early and sensitive index of r esponse of mercuric chloride effects, similar to total proteins and an giotensin converting enzyme. It is suggested that this enzyme is mainl y localized in the 'pars recta' of the proximal tubule. Therefore glut amine transaminase K might be a segment-specific marker for the detect ion of damage localized in this portion of the proximal tubule.