Comparison of sodium and stannous fluoride nephrotoxicity

Single i.p. injections of 0.5 mmol F-/kg and repeated i.p. injections of 0.25 mmol F-/kg as NaF or SnF2 to male rats showed that both compounds produced early lesions of kidney tubule demonstrated by an intense increase of urine gamma-glutamyl transferase (GGT). Disturbance of kidney function with an increase of diuresis and phosphaturia and a decrease of natriuria and kaliuria were more marked in SnF2-treated animals as was the decrease of urine GGT after a few days. These results indicate that tin nephrotoxicity adds to that of fluoride and antagonizes tubule regeneration.

Variants of gamma-glutamyl transferase in human urine

When dialyzed human urine was subjected to ultracentrifugation, gamma glutamyl transferase activity amounting to one-third or less of the total activity was found associated with the microsomal fraction and the remaining in the 100 000 X g supernatant. By ion-exchange chromatography on DEAE-cellulose at pH 7.5, the urinary enzyme was resolved into two fractions. The less anionic form (eluted with 0.15 mol/l NaCl) corresponded to the 100 000 X g supernatant fraction. The more anionic form (eluted with 0.5 mol/l NaCl) corresponded to the microsomal fraction. On chromatography on concanavalin A-sepharose, the urinary transferase activity separated into the unbound fraction and the bound fraction (eluted with alpha-methyl-D-glucoside). The bound fraction was retained more tightly on DEAE-cellulose (eluted with 0.5 mol/l NaCl). The unbound fraction had weaker interaction with the ionic-exchanger (eluted with 0.15 mol/l NaCl). Each of two fractions separated by affinity chromatography on concanavalin A-sepharose, resolved into two bands on cellulose acetate electrophoresis at pH 7.t. In addition, during gel chromatography on Sephadex G-200, they separated into a high molecular weight (greater than 200 000) fraction and a low molecular weight (55 000) fraction. The band that stayed at the origin during electrophoresis was high molecular weight in nature, whereas the fraction that moved towards the anode was found to be the smaller form of the enzyme. The study of the variants of urinary gamma glutamyl transferase was not found to be of clinical significance. The nature and origin of the variant forms of the enzyme in urine are discussed.

Neomycin toxicosis in calves

Calves (n = 4) were given neomycin (2.25 or 4.5 mg/kg) twice daily IM and were compared with 2 calves given penicillin IM. The 2 hallmarks of aminoglycoside toxicosis, nephrotoxicosis and ototoxicosis, were seen with both dosages of parenterally administered neomycin. Nephrotoxicosis was confirmed by abnormal findings in urinalysis (granular casts, proteinuria, low specific gravity), renal biopsy results (tubular degeneration and necrosis), and increased 24-hour amounts of urinary enzymes (alanine aminopeptidase and gamma-glutamyltranspeptidase). Azotemia, decreased creatinine clearance, polyuria, and polydipsia also were documented in calves given neomycin. Clinically, deafness was suspected in 2 calves and was documented by electrical auditory-evoked response tests. Abnormalities in partial thromboplastin times and renal residues of neomycin were seen in all 4 calves that were given neomycin, but not in calves that were given penicillin.

Enzymuria (the output of gamma-glutamyl-transpeptidase and of N-acetyl-beta-D-glucosaminidase) in the course of experimental renovascular hypertension

The urinary output of gamma-glutamyl-transpeptidase (gamma GT) and of N-acetyl-beta-D-glucosaminidase (NAG) was studied with "two-kidney Goldblatt hypertension' 3-6, 16-19 and 30-33 weeks after eliciting high blood pressure. gamma GT excretion rate of normotensive males was higher than that of females, while the activity of the renal tissue was on the same level. gamma GT output of hypertensive males was elevated in the early and in the middle stages of the disease, it was subnormal in the late stage. In females gamma GT output increased in animals with excessively high blood pressure (less than 200 mm Hg) only. gamma GT output correlated with the tissue activity in males only. In all animals there was an inverse, linear correlation between tissue gamma GT activity and the hydroxyproline content. The pattern of the NAG output was similar to that of gamma GT, however, excretion of NAG showed no sex differences and remained high in the late stage of the disease, too. Nephrosclerosis was less pronounced in female Goldblatt rats than in males.

Urinary gamma-glutamyl transferase as a specific marker for mercury after heavy metal treatment of rats

Male Sprague--Dawley rats were injected i.p. with 1 mg heavy metal (Cu, Rb, Cs, Zn, Sr, Cd, Ba, Zr, Pb, Mb, Fe, Co, Ni)/kg body weight, as chlorides and 24 h urine samples were analysed for gamma-glutamyl transferase (GGT) content. Mercury (Hg) was the only metal that induced an enhanced urinary GGT activity. We concluded that, when acute metal intoxication has been observed, urinary GGT may function as a specific marker for Hg intoxication. Gel permeation studies showed that increased tubular lesion accounts for the Hg-induced GGT increase.

Does renal tubular dysfunction account for the enhanced CAm/CCr ratio in acute pancreatitis?

To verify whether renal tubular dysfunction may account for the CAm/CCr enhancement in acute pancreatitis (AP), we have measured the renal excretion of amylase, lysozyme, and gamma-glutamyl-transpeptidase (GGTP) in 22 patients with AP and in 8 with acute tubular necrosis. While the CAm/CCr ratio was elevated in most patients with AP, the CLys/CCr ratio fell within the normal range in 60% of these patients. The subdivision of patients with AP in subgroups with elevated and normal CLys/CCr ratios revealed a mean CAm/CCr not statistically different. Moreover, no correlation was present in AP between amylase vs. both lysozyme and GGTP clearances. These data suggest that tubular dysfunction does occur in some but not in all the patients with AP and seems not to play a major role in the pathogenesis of the increased CAm/CCr ratio in this condition.

Ethionine and methionine distribution and toxicity in the rat kidney

Autoradiographic studies demonstrated that in the rat kidney radioactivity was localized mainly in the medulla in animals injected with [14C]ethionine, whereas it was distributed homogeneously throughout the whole parenchyma in rats given [14C]methionine. This difference of distribution was consistent with a difference in renal toxicity: a single i.p. dose (1 g/kg) of ethionine induced a slight but persistent (6 days) damage to kidney tubule cells evidenced by an increase of urinary GGT and slight disturbance of renal function, such damage was not observed with methionine.

Acute kidney toxicity of sodium fluoride in the rat

Single i.p injection of 0, 0.05, 0.10, 0.25, 0.50 and 1.00 mmol NaF/kg to male rats induced a dose-related increase of urine gamma-glutamyl transferase (GGT) elimination on the first day for all doses higher or equal to 0.25 mmol NaF/kg. Kidney damage began between 2--4 h following the injection and lasted only 12 h for the 0.50 mmol NaF/kg dose. There was an increase of diuresis and of phosphaturia even at lower doses.

[Evaluation of nephrotoxic site in rat proximal tubule: intrarenal distributions of three enzymes and effects of mercuric chloride and gentamicin on their excretion into urine (author's transl)]

Intrarenal distributions of three enzymes, gamma-glutamyl transpeptidase (gamma-GTP), alkaline phosphatase (Al-p) and leucine aminopeptidase (LAP) were determined using six segments of nephrons. These enzymes were localized only in the proximal tubule. Intra-proximal distributions of the enzymes, however, were not uniform. The order of each enzyme activity in three segments of the proximal tubule, S1, S2 and S3 was as follows: Formula: (See Text) With subcutaneous administration of HgCl2 (1.0 mg/kg/day), urinary excretions of all three enzymes were increased from the 1st to the 2nd day and then decreased to the control level. However, after intraperitoneal administration of gentamicin sulfate (40 mg/kg/day), only Al-p activity in urine was significantly increased on the 1st day. Because of the lack of increasing blood levels of these enzymes after treatment, increased urinary excretions of the enzymes probably originate from the kidney, particularly the proximal tubule. The prominently increased excretion of gamma-GTP and LAP after HgCl2 treatment means that HgCl2 might damage S2 and S3, because the excretory patterns of the three enzymes were similar to their distribution profiles in S2 and S3. On the other hand, the toxic action of GM may be localized in S1 portion, in which Al-p activity proved to be highest among the three enzymes.

The biochemical consequences of cardiopulmonary bypass surgery in children

The changes in serum enzyme activities after successful and uncomplicated cardiopulmonary bypass (CPB) surgery in children are described. After maximum serum enzyme activities were attained, they thereafter declined steadily without any secondary peaks of activity, to be at or near normal activities by the seventh day after surgery. The possible sources and mechanisms of enzyme leakage from tissues after CPB are discussed. The concentration of some physiologically important constituents were determined in pump prime fluids and in the common circulation on bypass. The consequences of haemodilution on small children were undesirably reduced concentrations of magnesium, calcium and albumin, and this state persisted for some days after the end of bypass. Some possible implications of such unphysiological pump primes are discussed. We suggest that ASp AT, Ala AT, CK-MB, magnesium, calcium and urea should be routinely monitored for the first four days after surgery.

Isolation of kidney brush border gamma-glutamyl transpeptidase from urine by specific antibody gel chromatography

The IgG fraction of antiserum directed against gamma-glutamyl transpeptidase (gammaGTP, EC 2.3.2.2) isolated from human kidney brush border membranes after limited proteolysis, was covalently bound to cyanogen bromide-activated Sepharose. With this antibody-gel, gammaGTP present in the urine of patients as a result of tubular damage was immunospecifically prepared by affinity chromatography. The enzyme isolated from the urine samples gave a complete cross-reaction wiht gammaGTP artificially cleaved off from brush border fragments. Since labelled anti-gammaGTP sera gave a specific immunofluorescence only of the luminal portion of cortical tubule, the use of immunosorption chromatography appears to be an important approach for the isolation of urinary kidney tissue antigens of a defined origin.

[Protection against mercuric chloride nephropathy by sodium selenite in the rat]

Daily intraperitoneal injection of 2.5 or 5 mumole HgCl2 to male Rats weighing 250 to 350 g induces an early intense increase of urine gamma-glutamyl transferase activity. In the same conditions, equimolecular administration of sodium selenite and mercuric chloride induces no increase of the enzymuria for the low dose: for the high dose- a minor and more persistent increase of urine GGT is observed. Thus, the activity of urines GGT allows, in vivo, to establish that sodium selenite protects Rat kidney against toxic effects of mercuric chloride.

Urine gamma-glutamyl transferase in rat kidney toxicology: nephropathy by repeated injections of mercuric chloride. Effects of sodium selenite

Groups of 5 male and 4 female Cobs CD rats weighing 250--350 g were injected intraperitoneally, daily for 15 days, with 5 mumol HgCl2/kg, 5 mumol Na2SeO3/kg, or (5 mumol HgCl2 + 5 mumol Na2SeO3)/kg in a 10 ml/kg vol. of saline. Control animals were injected with saline only. Injection of saline or sodium selenite produced neither modification of diuresis, nor of urine elimination of sodium, potassium, chloride, phosphates, urea, creatinine and gamma-glutamyl transferase (GGT). Injection of mercuric chloride induced a massive increase of urine GGT, diuresis and phosphaturia and a decrease of kaliuria and natriuria. Those effects reflect a kidney tubular lesion which seems to be more severe in males than in females. Injection of mixed sodium selenite and mercuric chloride or separate injection of both compounds had similar effects. In both sexes, urine GGT elimination was delayed and about 2 times lower than with HgCl2 alone. In females, the other urine parameters were almost normal whereas in males, diuresis and phosphaturia were slightly increased and kaliuria decreased. The observation of urine GGT elimination attests, in vivo, that sodium selenite decreases tubular toxicity of mercuric chloride and resulting kidney function disturbances.