The effect of mercuric chloride intoxication on urinary psi-glutamyl transpeptidase excretion in the sheep

The activity of the enzyme psi-glutamyl transpeptidase (psi-GT) was measured in the urine of sheep. In clinically normal animals the mean value was 6-3+/-0-6 mU/ml. In sheep with kidney damage induced by the administration of mercuric chloride there were marked increases in urinary concentrations of psi-GT, in some cases values in excess of 1000 mU/ml were recorded. This enzyme may be of value in the diagnosis of certain forms of renal disease.

Diagnosis of renal tumor by gamma-glutamyltranspeptidase (EC 2.3.2.2)

A urinary enzyme pattern and kidney tissue pattern were investigated simultaneously in 117 urologic patients. In contrast to all other renal disorders only the sixteen malignant tumors of the kidney showed a significant drop of gamma-GT in tumor tissue and urine. So far urinary enzymology has been used only as screening test. Measurement of gamma-GT in urine, however, permits the diagnosis of kidney tumors.

A stabilising factor for gamma-glutamyl transpeptidase in urine

Urinary gamma-glutamyl transpeptidase (gamma-GT) has been found to be stable when stored at room temperature and 4 degrees C. Activity is lost rapidly when urine is frozen but prior dialysis will prevent this loss. Urea is the major factor responsible for the loss of activity; albumin is protective at concentrations of 6 g/l or more. A factor of 10 000-30 000 molecular weight which will prevent the loss of urinary gamma-GT activity on freezing has been found in serum and urine; it has high potency in serum and in urine from patients with chronic renal failure, but only low potency in normal urine. Its nature is unknown but it is heat stable.

Urinary gamma-glutamyl transpeptidase, an indicator of renal ischaemic injury and homograft rejection

Gammaglutamyl transpeptidase is an enzyme primarily located in the brush border of the proximal convoluted tubules of the kidney. Its unique localisation in the renal cells most easily damaged by ischaemia and its ease of assay provides the rationale for its use in the measurement of renal ischaemic injury. Using a standard experimental animal model, canine urinary gamma-GT activity was shown to be increased up to 70-fold following 90 min of unilateral renal ischaemia and was significantly raised following only 5 min ischaemia. The urinary gamma-GT was used as a measure of ischaemic injury associated with renal transplantation in man and 20 consecutive patients undergoing kidney transplant were studied by daily 24-hour urinary gamma-GT estimations and excellent correlation was obtained between raised enzyme activity and the clinical diagnosis of transplant rejection.

Gamma-glutamyl transpeptidase. A sensitive indicator of renal ischaemic injury in experimental animals and renal homograft rejection in man

The sites of ischaemic injury within the kidney are reviewed and the diagnostic value of measurements of plasma and urinary enzymes in renal ischaemic injury and in renal homotransplant rejection in experimental animals and man is examined. Gamma-glutamyl transpeptidase (gamma-GT) is an enzyme primarily located in the brush border of the proximal convoluted tubule of the kidney. Its unique localization in the cells most easily damaged by ischaemia and its ease of assay provide the rationale for its use in the measurement and diagnosis of renal ischaemic injury. gamma-GT activity was measured in dogs undergoing varying periods of renal ischaemia and under conditions of local renal hypothermia and was shown to be a sensitive indicator of ischaemic injury. Twenty consecutive patients undergoing renal homotransplantation were studied by daily estimation of their 24-h urinary gamma-GT activity; excellent correlation was obtained between raised levels of this enzyme and the clinical diagnosis of transplant rejection.

Investigations of the excretion of gamma-glutamyl-transpeptidase into the urine

The excretion of the enzyme gamma-glutamyl-transpeptidase and its isoenzymes into the urine was investigated in patients with renal diseases and compared with the excretion of the enzymes leucine-aminopeptidase and lactate-dehydrogenase. In animal experiments an increased excretion of these enzymes was found after autotransplantation. Increased excretion of gamma-glutamyl-transpeptidase was also found in patients with glomerulonephritis and in the polyuric phase of acute tubular necrosis, but not in cases of pyelonephritis and in the oliguric phase of acute tubular necrosis. The alterations of the isoenzyme pattern during diseases with increased enzyme excretion are in accordance with the hypothesis that the enzymes are liberated from the kidney tissue into the urine, and only a minority stems from the blood. Investigation of the excretion of gamma-glutamyl-transpeptidase and its isoenzymes into the urine seems to be of both scientific and clinical interest.

[The effect of therapeutic gentamycin doses on the enzyme secretion in urine]

8 patients with chronic pyelonephritis were given gentamycin intramuscularly injected in individual dosage during 8-10 days. Here the behaviour of the excretion of protein, alanine aminopeptidase alkaline phosphatase, alpha-glucosidase, gamma-glutamyl transpeptidase and lysozyme with the urine was tested. With the exception of the lysozymuria, which increased only in patients with chronic renal insufficiency, regularly a hyperenzymuria developed. Most distinctly the excretion of the alanine aminopeptidase increased. After initial decrease the excretion of total protein transiently increased after completion of the gentamycin therapy. All the deviations were reversible. From the increased excretion of enzymes may not be concluded to a nephrotoxicity of gentamycin.

Nephron function in acute glycerol-induced renal insufficiency in rabbits

The effect of acute experimentally induced renal failure after intramuscular injection of glycerol on serum and urine GGTP, LAP and AP activities was studied in 30 rabbits. High doses of glycerol caused shock, myolysis and hemolysis, leading to acute renal insufficiency. Serum urea and creatinine levels significantly increased, there was proteinuria, and significant decrease in 24-hr diuresis, glomerular filtration, and urinary urea excretion. The changes in LAP and AP activities were significant, and in GGTP-nonsignificant. In the urine GGTP and LAP increased significantly, and AP nonsignificantly. Urinary excretion of AP increased significantly, and GGTP and LAP nonsignificantly. The highest activity and urinary excretion of GGTP and LAP were observed on the 2nd day, and of AP--on the 5th day of renal failure.