Elevation of urinary trehalase in mercuric chloride-induced nephrotoxic rabbits: urinary trehalase as a specific indicator of renal brush border damage.

The origin of urinary trehalase in mercuric chloride-induced nephrotoxic rabbits was demonstrated with biochemical and immunochemical techniques. Urinary trehalase was dramatically increased with HgCl2-induced nephrotoxicity. The nephrotoxic kidney showed an extreme decrease in specific fluorescence with fluorescein isothiocyanate (FITC)-conjugated antibody technique. Moreover, trehalase activity in the membrane fraction was remarkably decreased in the nephrotic kidney compared with the control. Judging from the results of immunodiffusion, urinary trehalase and renal trehalase exhibit the same antigenicity. From the data of a time course analysis of nephrotoxicity, the excretion of urinary trehalase was earlier than that of urinary sugar. Previous results show that renal trehalase is localized in the renal tubular brush borders. From these results, it is suggested that urinary trehalase is originated in the renal brush borders. In consideration of the results described in previous papers and in this paper, it is proposed that urinary trehalase is a good indicator of renal brush border damage.