Studies on the validity of urinary enzyme assay in the diagnosis of drug-induced renal lesions in rats

Abstract

The validity of urinary enzyme assays in the diagnosis of renal lesions was studied in rats for evaluation in comparison with other tests such as urinalysis and serum biochemical assay. Tubular damages of slight or severe degree were induced by daily intramuscular administration of 500 mg/kg or 1,000 mg/kg of kanamycin (KM) for 7 and 6 days respectively. Glomerular lesions were induced subcutaneous injection of 30 mg/kg of puromycin (PM) for 6 days. The enzymes, assayed daily before and after the onset of administration, were lactic dehydrogenase (LDH), aspartate aminotransferase (GOT), alkaline phosphatase (AI-P), acid phosphatase (Ac-P), leucin aminopeptidase (LAP) and γ-glutamyl transpeptidase (γ-GT). The distribution of these enzymic activities in the kidneys was histochemically examined. Assays of LDH and GOT on the kidney tissue homogenate were also conducted. Histological alterations of the kidneys were examined in the rats sacrificed after termination of administration.

Significant elevation of the LDH and GOT urine levels were observed within 24 hours in rats treated with 500 mg/kg of KM with the high enzyme levels being maintained throughout the administration period, while the other enzymes remained within pretreatment levels or were only slightly elevated. Serum urea nitrogen (BUN) and creatinine levels remained unchanged with no abnormality being found in the urinalysis of this group. In the group treated with 1,000 mg/ kg of KM, concomitant rising of all urine enzyme levels was observed, with elevation of the LDH and GOT levels being extreme while the BUN and serum creatinine levels rose only at the termination of the administration period. The BUN level rose earlier than did most of the urinary enzymes in puromycin-treated rats.

Depletion of LDH activity was histochemically demonstrated in the kidneys where no histological alteration was observable, while the activities of AI-P, γ-GT, and LAP showed no distinct changes until the tabular destruction became severe. Upon termination of both KM and PM administration, the depletion of LDH and GOT activities was noted in a kidney homogenate assay for the enzymes.

These results clearly showed that among the enzymes studied, the LDH and GOT urine levels are the most sensitive indicators for detecting proximal tubular lesions induced by KM. It was further demonstrated that the urinary enzyme assay in combination with serum BUN measurement is an effective examination for distinguishing tubular from glomerular lesions.

References

1. Pollak VE , Bonting SL , Muehrcke RC , Kark RM : Quantitative histochemistry of the nephron. IV. Alkaline phosphatase and lactic dehydrogenase activities in renal tubular diseases. J Clin Invest 39:1386–1393, 1960.

2. Price RG , Dance N , Robinson D : A comparison of the β-glycosidase excretion during kidney damage induced by 4-nitrophenylarsonic acid and by rabbit anti-rat kidney antibodies. Eur J Clin Invest 2:47–51, 1971.

3. Ellis BG , Price RG , Topham JC : The effect of tubular damage by mercuric chloride on kidney function and some urinary enzymes in the dog. Chem Biol Interact 7:101–113, 1973.

4. Sternberg M , Szlamka I , Moisy M et al : Comparison of the urinary excretion of aspartate aminotransferase, lactic dehydrogenase, alkaline and acid phosphatase and β-galactosidase during nephrotoxic serum glomerulonephritis and mercuric chloride tubulonephritis in the rat. Z Klin Chem Klin Biochem 12:543–550, 1974.

5. Wellwood JM , Lovell D , Thompson AE , Tighe JR : Renal damage caused by gentamicin: A study of the effects of renal morphology and urinary enzyme excretion. J Pathol 118:171–182, 1975.

6. Raab WP , Moerth CM : Probenecid and the rat kidney: investigations by renal enzyme excretion technique. Int J Clin Pharmacol Biopharm 13:120–122, 1976.

7. Ward JP : Urinary gamma-glutamyl transpeptidase, an indicator of renal ischaemic injury and homograft rejection. Br J Urol 47:765–770, 1976.

8. Cunningham RG , Carvajal HF , Passey RB : Urinary LDH isoenzyme 5 excretion in experimental pyelonephritis. Br J Exp Pathol 58:220–224, 1977.

9. Bhargava AS , Khater AR , Günzel P : The correlation between lactate dehydrogenase activity in urine and serum and experimental renal damage in the rat. Toxicol Lett 1:319–323, 1978.

10.

10. Kirschbaum BB : Alanine aminopeptidase excretion after mercuric chloride renal failure. Biochem Med 21:220–225, 1979.

11.

11. Price RG : Studies on the nephrotoxicity of p-nitrophenyl-arsonic acid: changes in rat kidney and urinary enzyme activities following the administration of p-nitrophenylarsonic acid. Chem Biol Interact 24:241–255, 1979.

12.

12. Tsurumi K , Abe A , Nozaki M , Fujimura H : Influence of some anti-inflammatory, antipyretic and analgesic agents on urinary enzyme level in rats. J Toxicol Sci 3:1–9. 1978.

13.

13. Burgat-Sacaze V , Braun JP , Rico A , et al : Methoxy-ethylmercury nephrotoxicity: Effects on enzymuria and kidney function. Arch Toxicol 43:227–231, 1960.

14.

14. Raab WP : Diagnostic value of urinary enzyme determinations. Clin Chem 18:5–25, 1972.

15.

15. Szasz VG : γ-Glutamyltranspeptidase-aktivität im urin. Z Klin Chem Klin Biochem 8:1–8, 1970.

16.

16. Watanabe M , Tanaka H , Funakawa K , Nagase S : Urinary protein analysis in experimental renal injuries in rats. (Abst.) J Toxicol Sci 2:101, 1977.