Effect of single and multiple doses of sulphinpyrazone on antipyrine metabolism and urinary excretion of 6-beta-hydroxycortisol

Sulphinpyrazone decreases the plasma clearance of tolbutamide and S-warfarin and increases the clearance of R-warfarin, theophylline and antipyrine. In order to determine whether sulphinpyrazone is an inducer or inhibitor or both of oxidative drug metabolism, antipyrine and its metabolites as well as 6-beta-hydroxycortisol were measured in urine before, 24 h and after 23 days of chronic administration of sulphinpyrazone (4 X 200 mg/day). During chronic treatment sulphinpyrazone increased the ratio of 6-beta-hydroxycortisol to the 17-hydroxycorticosteroids by 70% (p less than 0.02). The renal clearance of the main oxidative metabolites of antipyrine (4-hydroxyantipyrine, 3-hydroxymethylantipyrine and norantipyrine) were increased after sulphinpyrazone (p less than 0.02). Except for norantipyrine, no change in total excretion of antipyrine and its metabolites occurred after 24 h or after 23 days. It is concluded that sulphinpyrazone induces the enzymes which metabolize antipyrine and cortisol.

[Methodological aspects of urinary enzymology]

Collection and storage of the sample exert significant influences on the results of urinary enzyme determinations. Enzymes with sufficient stability during urine collection and consecutive in vitro storage are probably best suited for diagnostic purposes. Sample preparation, e.g. by gel filtration of the urine should be performed to remove quantitatively interferences. Optimized methods for some urinary enzymes are now available offering a basis for standardization. Analytical results should be verified by the use of self-prepared or commercially available quality control materials. The modern clinical chemical technology permits the determination of enzyme activities in urine with a quality standard comparable to that in other body fluids. New approaches are the development of a dipstick test for beta-N-acetylglucosaminidase and the use of immunological techniques for the measurement of enzyme concentrations in urine.

[Renal enzyme excretion in tumors and tumor therapy]

None of the hitherto investigated enzymes of the urine can be used as marker for the proof of tumours. Hopeful starts in this respect are to be seen in an increased beta-glucuronidase excretion and in a decreased gamma-glutamyl transpeptidase excretion as well as in an increased LDH5/LDH1 ratio. The lysozyme excretion with the urine gives important references to the differential diagnosis, the assessment of the prognosis and therapy of acute leucoses. An importance obtained enzyme determinations in the urine for the clarification of pathobiochemical processes of the alteration of the kidney by neoplasms, tumour-lysis-syndromes, cytostatics, tumour radiation and operations of tumours. Courses of enzyme excretion during tumour therapy which as a rule show a rhythmic hyperenzymuria allow conclusion to the moment of the flow the catabolic products of the tumour at the kidney and to the different reaction of the tubular epithelium to these substances.

[Assessment of drug nephrotoxicity by the excretion of tubule-specific membrane antigens and enzymes]

A possible tubulotoxicity of drugs can be judged with the help of the excretion of tubular membrane proteins in the urine. The brush border of the proximal tubular epithelia which react particularly sensitive to toxic influences contains surface antigens which easily release themselves from the membrane core membrane under pathological conditions and become provable in the urine by means of biochemical and immunological methods as signs of an early structural cell damage. Apart from these soluble membrane proteins which above all correspond to enzymes such as alanine aminopeptidase and gamma-glutamyl transpeptidase in severe lesions high molecular brush border fragments transformed to vesicles can appear. The clinical relevance of a pathological tissue proteinuria (histuria) of proteins of renal membranes is among others explained at the instance of the renal effects of cytostatics, antibiotics and x-ray contrast medias.

[Urinary enzyme excretion in kidney transplant patients]

In a survey the present state of the activity determination of urinary enzymes after kidney transplantation as a diagnostic tool in the control of patients with transplanted kidney is described. A great number of enzymes has up to now been established in these patients. The most extensive data are present for the enzymes alanine-aminopeptidase, N-acetyl-beta-D-glucosaminidase and lysozyme. After the transplantation of the kidney typical excretion patterns of the enzymes in the urine are observed in immediate function, retarded onset of the function, without function and acute rejection of the graft. Particularly the behaviour of the urinary enzyme excretion during acute rejection reactions can be diagnostically used. Hereby, the diagnostic reliability of determinations of the activity of urinary enzymes is, however, differently assessed by various authors. In future works in close cooperation between clinic and laboratory the diagnostic validity of the determinations shall unambiguously be characterized and the determinations of the enzyme activity in the urine should be summarized together with other parameters to an optimum combination of parameters for the follow-up investigation of patients who underwent kidney transplantation.

Comparative study of alanine-amino-peptidase and gamma-glutamyl-transferase activity in normal Wistar rat urine

24 h urinary alanine-amino-peptidase (AAP) and gamma-glutamyl transferase (GGT) activities were studied from the 3rd-7th month of life in male Wistar rats. A close relationship was found between AAP and GGT activity, except at the beginning and at the end of this period. At the end there appear 2 subgroups, the larger (70%) showing a strong correlation between AAP and GGT activity and the other (30%), demonstrating no correlation at all. A good correlation between AAP and GGT activities, creatinine, 24 h urine volume and 24 h creatinine output was found.

Increased urinary excretion of renal enzymes in idiopathic calcium oxalate nephrolithiasis

Urinary excretion of gamma-glutamyl transpeptidase, angiotensin I converting enzyme, beta-galactosidase and N-acetyl-beta-glucosaminidase was evaluated in 30 patients with idiopathic calcium oxalate urolithiasis. Higher than normal values were observed and the excretory enzyme pattern suggested tubular damage in patients with stones. A parallel study in the rat showed that an oxalate surcharge can promote increased urinary excretion of these enzymes. It is known that urothelium injury may enhance crystal adhesion. If the damage is primary it may be viewed as a promoting factor. If it is secondary it may be considered a factor capable of increasing salt precipitation.

The activity of membrane enzymes in homogenate fractions of rat kidney after administration of lead

Rats received one or two consecutive daily ip injections, each 0.5 mg Pb2+/100 g body weight, and the kidneys were studied 48 or 24 hr, respectively, after the injection. Renal brush border preparations from Pb2+-treated rats exhibited significant decreases in the activity of alanine aminopeptidase and gamma-glutamyl transpeptidase, greater after two injections, yet the amount of brush border protein remained unchanged. Moreover, the activity of alkaline phosphatase in the brush border was significantly increased after Pb2+. No significant changes in urine volume, urinary protein, or enzymes could be detected in these experiments. The enzymatic changes observed in the brush border after acute exposure to Pb2+ contrasted with those after exposure to Hg2+ where both the structure and enzymatic functions were severely damaged and after exposure to Cd2+ where enzymatic alterations were not accompanied by cytological changes.

Comparison of methods for preservation of renal function during ischemic renal surgery

Three methods of providing in situ protection to an ischemic kidney were compared in dogs. These were surface cooling using external coils, transvenous hypothermic perfusion and intravenous inosine. The dogs were divided into 3 groups with 20 dogs in each group. Group 1 had the artery occluded for 45 minutes, group 2 for 60 minutes and group 3 for 90 minutes. A further control group of 5 dogs underwent mobilization of the left kidney without ischemia. Contralateral nephrectomy was performed on all animals. The 20 dogs in each group were randomized; 5 undergoing surface cooling, 5 cooling by renal vein perfusion, 5 receiving intravenous inosine and 5 receiving no protection. Function of the solitary kidney was monitored by serum creatinine levels. All 3 methods provided significant protection. Protection provided by surface cooling and inosine was greater than by venous cooling. The protection provided by intravenous inosine was similar to surface cooling for up to 60 minutes but was less at 90 minutes.

Gamma-glutamyl transpeptidase activity in human urine

The gamma-glutamyl transpeptidase (EC 2.3.2.2) activity of the urine was determined in 369 cases, with L-gamma-glutamyl-p-nitranilide as substrate. Thermally stable, low molecular mass inhibitors were removed by dialysis. The enzyme activity was found to have a mean of 10.57 U/l for the normal neonate population, and a mean of 16.92 U/l for children. A significant increase in activity was observed in pyelonephritis, Alport's syndrome, Wilms' tumour and glomerulopathies. The highest activities were found in kidney diseases associated with renal insufficiency. This non-invasive test can be used for the evaluation of tubular disorders in childhood.

Urinary enzyme excretion by renal-transplant recipients in relation to interval after transplantation

We determined the urinary excretion of the enzymes aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-glucosaminidase (EC 3.2.1.30) in two groups of renal-transplant recipients at different times after transplantation (1.8 months and 52 months, respectively). Both groups of patients showed a higher rate of enzyme excretion than did a reference group of healthy persons. More aminopeptidase and N-acetyl-beta-glucosaminidase were excreted during the early period after transplantation than later. The time-dependence of urinary enzyme excretion was confirmed in six renal-transplant recipients studied during the course of 15 months after transplantation. There was a general correlation between the extent of urinary enzyme excretion and both the time after transplantation and the daily dose of prednisolone. Therefore, it is necessary to take into account this influence on the extent of urinary enzyme in renal-transplant recipients if urinary enzyme excretion is used as an indicator of renal disorder and especially as an early predictor of transplant rejection.

[Urinary enzymologic diagnosis]

In theory it can be accepted today that the analysis of urinary enzymes has a certain diagnostic value; this enables the diagnosis and observation of kidney damage to be improved without any more drastic measures. Thus it should be possible to recognize new aspects of kidney diseases which cannot be recognized using other, intensive methods. In future urologists and nephrologists should strive to investigate the following problems, relying on adequate documentation of the respective state of the urorenal system: --induction of functional and lesional changes using diagnostic and therapeutic means--evaluation of the effects of medicaments on urinary enzymes--the response of urinary enzymes to infections of the urorenal system--the correlation between the functioning of a transplant and the enzyme pattern in the urine--the search for enzyme markers in patients with cancers of the urogenital tract. The analysis of urinary enzymes is not to be recommended as a method of searching for kidney disease today. Diagnosis through urinary enzymes should not be used as a rule. Our aim for the future should be to use automated biochemical methods with the aid of computer analysis and programming for studies on urinary enzymes.

[Urinary elimination of multiple forms of gamma-glutamyltranspeptidase and aminopeptidase (author's transl)]

Concentrated and dialyzed 24-h urines of healthy persons were separated by 105000 X g ultracentrifugation into a pellet (P105) and a supernatant (S105) fraction. Chromatography of the P105 fraction on Sepharose 4B and 2B revealed that gamma-glutamyltranspeptidase and aminopeptidase activities had a molecular mass of 20 X 10(5) to 40 X 10(6), whereas in the S105 fraction soluble gamma-glutamyltranspeptidase and aminopeptidase had 86000 and 160000, respectively. Triton X-100 solubilization was performed on the P105 fraction and on a human renal cortex 40000 X g pellet, used as a reference. All the activity was recovered in both cases in a single peak of detergent gamma-glutamyltranspeptidase and detergent aminopeptidase eluted by filtration on Ultrogel Ac A22. Apparent molecular mass of Triton X-100 solubilized urinary and renal enzymes were 250000 and 243000 for gamma-glutamyltranspeptidase, and 298000 for both aminopeptidases. Protease solubilized forms were obtained by trypsic digestion of detergent urinary and renal forms. Both gamma-glutamyltranspeptidases were found to have an apparent molecular mass of 86000 on Sephadex G 150, which is identical to the value found for the S105 urinary gamma-glutamyltranspeptidase. The aminopeptidases had 238000 and 232000, which is a higher value than the molecular mass of the S105 urinary aminopeptidase. This letter could be a degraded form of the renal aminopeptidase. These findings suggest that gamma-glutamyltranspeptidase and aminopeptidase in the P105 fraction are similar to native renal enzymes. Evaluation of the P105 fraction enzymatic activities may thus be useful in the diagnosis of tubular damage.

Urinary enzyme excretion and renal lactate dehydrogenase isoenzyme pattern in acute HgCl2 nephropathy of rat

The activity of several enzymes with different intracellular sites was determined in urine at various times following nonfatal acute tubular necrosis induced by mercuric chloride administration. The excretion rate of all tested enzymes rose on the 1st and 2nd day; in the next observations (days 7-15) enzymatic values approached the basal values. The lactate dehydrogenase isoenzyme pattern of the renal cortical zone showed an early shift towards cathodic fractions and later (7 days) an increase of middle ones; the normal anodic zymogram recovered after a suitable time interval (30 days). The isoenzymatic changes are related both to the renal hypoxia and to the appearance of less differentiated cells. The behaviour of functional parameters (urine flow, osmolality, urea clearance, creatinine clearance) were well in agreement with the observed enzyme and renal isoenzyme changes.

Proteinuria after burn injury

Qualitative and quantitative aspects of the excretion of protein after burn injury have been investigated. The excretion of total protein and of albumin have been measured nephelometrically while the excretion of proteins of both serum and non-serum origin have been measured by immunoelectrophoresis using antiserum against serum proteins or against a pool of urine from burned patients. Comparison of the patterns of proteins observed in urine using these two different antisera showed the presence of at least three major proteins that did not originate from the plasma. The excretion of two of these three proteins followed closely the pattern of total protein excretion which reached a maximum at five to seven days after injury. The excretion of albumin was greatest in the first 48 hours after injury. Examination of the original burn patients' urine antigen by sodium dodecyl sulphate polyacrylamide gel electrophoresis showed that this urine pool contained greater amounts of lower molecular weight proteins than were observed in a pool of normal urines. The observations suggest that a biphasic renal pathophysiology is observed after burn injury. Initially, there develops a mild transient glomerular lesion which progresses to a different state which shows at least some of the features of a tubular proteinuria.

Urinary gamma-glutamyl transferase as an indicator of acute nephrotoxicity in rats

A series of nephrotoxic compounds dissolved in 0.9% NaCl was given to groups of five male Wistar rats in a single i.p. injection. Mercuric acetate and mercuric trifluoroacetate at 1 mg Hg/kg induced a sharp increase in urinary gamma-glutamyl transferase (GGT) activity on day 1, followed by a decrease below control values on day 3. Sodium ethylmercurithiosalicylate induced a relatively small urinary GGT increase, explained by its low Hg-bioavailability. An increased urinary GGT activity was noted after treatment with the aminoglycoside antibiotics kanamycin, neomycin, paramomycin, and streptomycin (100 and 800 mg/kg), ammonium fluoride (18.5 and 37 mg/kg), potassium bichromate (7.5 and 30 mg/kg), sodium tetrathionate (62.5 and 125 mg/kg), and cis-diamminedichloroplatinum (2 and 4 mg/kg). This was lower than for the mercury compounds, but clearly different from the controls. The urinargy GGT increase was an acute phenomenon. It is concluded that the measurement of urinary GGT can be used as an indicator of acute nephrotoxicity.

Evaluation of renal tubular damage in liver cirrhosis by urinary enzymes and beta-2-microglobulin excretions

To assess the renal tubular damage in liver cirrhosis the fractional clearances of beta-2-microglobulin (B2m-fr.cl) and malate-dehydrogenase (MDH-fr.cl) were measured respectively in sixty-four and in forty-six out of seventy-nine patients with liver cirrhosis of different aetiology; furthermore the fractional excretions of gammaglutamyl-transpeptidase (fr-GGT) and of alpha-glucosidase (fr-AGL) were determined in fifty-three and in forty of them respectively. In all patients glomerular filtration rate (GFR) and renal plasma flow (RPF) were also measured. Twenty-five subjects were studied as a control group for the enzyme excretions, sixteen for B2m-fr.cl. B2m-fr.cl and MDH-fr.cl--indexes of tubular functions--on the average were normal and only slightly increased respectively in cirrhotics compared to controls. Nevertheless fr-GGT and fr-AGL--indexes of cytolysis of tubular cells--on the average were massively increased in cirrhosis compared to controls, particularly in those with reduced RPF and/or GFR. No clear relationship between the indexes of tubular damage studied and the indexes of liver function was found. Our results show that (1) A renal tubular anatomical damage was found by means of an increase in the release of enzyme from tubular cells in patients with liver cirrhosis, particularly in those with a significant reduction of RPF and/or GFR; even so renal reabsorption of low molecular weight proteins is generally maintained. (2) The tubular damage does not seem to be related to the degree of liver impairment.

Urine and serum leucine aminopeptidase, N-acetyl-beta-glucosaminidase and gamma-glutamyl transpeptidase activities in diabetics with and without nephropathy

Urinary and serum activities of leucine aminopeptidase (LAP), N-acetyl-beta-glucosaminidase (ABG) and gamma-glutamyl transpeptidase (GGTP) were determined in four groups: 1) control subjects with normal oral glucose tolerance test and normal renal function; 2) latent diabetics with elevated oral glucose tolerance test and diabetic parents; 3) overt diabetics; 4) diabetics with slight nephropathy, exemplified by elevated serum creatinine levels and decreased creatinine clearance. No clear differences were found in the urinary GGTP and serum enzyme activities. Urinary LAP activity was significantly increased in Groups 2, 3 and 4, and urinary ABG activity in Groups 3 and 4. However, since the rise in urinary LAP activity was less consistent than that in ABG, it seems that the appearance of the latter enzyme in urine most likely results from tubular damage and may serve as a sensitive indicator of early diabetic kidney disease.