Coordinately increased lysozymuria and lysosomal enzymuria induced by maleic acid

Coordinately increased lysozymuria and lysosomal enzymuria induced by maleic acid. During the acute renal tubular dysfunction of Fanconi syndrome and type 2 renal tubular acidosis (FS/RTA2) induced by maleic acid in the unanesthetized dog, we observed: 1) 30 minutes after the onset of FS/RTA2, the urinary excretion of lysosomal enzymes, N-acetyl-β-glucosaminidase (NAG), β-glucuronidase (β-gluc) and β-galactosidase (β-galac), increased simultaneously with the anticipated increase in renal clearance of lysozyme; 2) the severities of all these hyperenzymurias increased rapidly, progressively, and in parallel, all reaching a peak some 60 to 80 minutes after their onset; 3) thereafter, while the FS/RTA2 continued undiminished in severity, the severity of the hyperenzymurias decreased rapidly, greatly, progressively, and in parallel; and 4) sodium phosphate loading strikingly attenuated the FS/RTA2 and the hyperenzymurias. Thus, the maleic acid–induced FS/RTA2 is attended by an acute reversible–complex derangement in the renal tubular processing of proteins that: a) affects not only lysozyme which is normally filtered, but also NAG and other lysosomal enzymes, which are not; and b) is to some extent functionally separable from that of FS/RTA2. The findings suggest that the derangements in renal processing of lysozyme and lysosomal enzymes are linked, and that a phosphate–dependent metabolic abnormality in the proximal tubule can participate in the pathogenesis of both these derangements and the FS/RTA2