[Urinary gamma-glutamyl transferase in renal toxicology of the rat. Bases of its use and significance in acute mercurial nephritis]

Bisphosphonates to reduce bone fractures in stage 3B+ chronic kidney disease: a propensity score-matched cohort study

BACKGROUND

Bisphosphonates are contraindicated in patients with stage 4+ chronic kidney disease. However, they are widely used to prevent fragility fractures in stage 3 chronic kidney disease, despite a lack of good-quality data on their effects.

OBJECTIVES

The aims of each work package were as follows. Work package 1: to study the relationship between bisphosphonate use and chronic kidney disease progression. Work package 2: to study the association between using bisphosphonates and fracture risk. Work package 3: to determine the risks of hypocalcaemia, hypophosphataemia, acute kidney injury and upper gastrointestinal events associated with using bisphosphonates. Work package 4: to investigate the association between using bisphosphonates and changes in bone mineral density over time.

DESIGN

This was a new-user cohort study design with propensity score matching.

SETTING AND DATA SOURCES

Data were obtained from UK NHS primary care (Clinical Practice Research Datalink GOLD database) and linked hospital inpatient records (Hospital Episode Statistics) for work packages 1-3 and from the Danish Odense University Hospital Databases for work package 4.

PARTICIPANTS

Patients registered in the data sources who had at least one measurement of estimated glomerular filtration rate of < 45 ml/minute/1.73 m2 were eligible. A second estimated glomerular filtration rate value of < 45 ml/minute/1.73 m2 within 1 year after the first was requested for work packages 1 and 3. Patients with no Hospital Episode Statistics linkage were excluded from work packages 1-3. Patients with < 1 year of run-in data before index estimated glomerular filtration rate and previous users of anti-osteoporosis medications were excluded from work packages 1-4.

INTERVENTIONS/EXPOSURE

Bisphosphonate use, identified from primary care prescriptions (for work packages 1-3) or pharmacy dispensations (for work package 4), was the main exposure.

MAIN OUTCOME MEASURES

Work package 1: chronic kidney disease progression, defined as stage worsening or starting renal replacement. Work package 2: hip fracture. Work package 3: acute kidney injury, hypocalcaemia and hypophosphataemia identified from Hospital Episode Statistics, and gastrointestinal events identified from Clinical Practice Research Datalink or Hospital Episode Statistics. Work package 4: annualised femoral neck bone mineral density percentage change.

RESULTS

Bisphosphonate use was associated with an excess risk of chronic kidney disease progression (subdistribution hazard ratio 1.12, 95% confidence interval 1.02 to 1.24) in work package 1, but did not increase the probability of other safety outcomes in work package 3. The results from work package 2 suggested that bisphosphonate use increased fracture risk (hazard ratio 1.25, 95% confidence interval 1.13 to 1.39) for hip fractures, but sensitivity analyses suggested that this was related to unresolved confounding. Conversely, work package 4 suggested that bisphosphonates improved bone mineral density, with an average 2.65% (95% confidence interval 1.32% to 3.99%) greater gain in femoral neck bone mineral density per year in bisphosphonate users than in matched non-users.

LIMITATIONS

Confounding by indication was a concern for the clinical effectiveness (i.e. work package 2) data. Bias analyses suggested that these findings were due to inappropriate adjustment for pre-treatment risk. work packages 3 and 4 were based on small numbers of events and participants, respectively.

CONCLUSIONS

Bisphosphonates were associated with a 12% excess risk of chronic kidney disease progression in participants with stage 3B+ chronic kidney disease. No other safety concerns were identified. Bisphosphonate therapy increased bone mineral density, but the research team failed to demonstrate antifracture effectiveness.

FUTURE WORK

Randomised controlled trial data are needed to demonstrate antifracture efficacy in patients with stage 3B+ chronic kidney disease. More safety analyses are needed to characterise the renal toxicity of bisphosphonates in stage 3A chronic kidney disease, possibly using observational data.

STUDY REGISTRATION

This study is registered as EUPAS10029.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 17. See the NIHR Journals Library website for further project information. The project was also supported by the National Institute for Health Research Biomedical Research Centre, Oxford.

Nephrotoxicity from chemotherapeutic agents: clinical manifestations, pathobiology, and prevention/therapy

Nephrotoxicity remains a vexing complication of chemotherapeutic agents. A number of kidney lesions can result from these drugs, including primarily tubular-limited dysfunction, glomerular injury with proteinuria, full-blown acute kidney injury, and long-term chronic kidney injury. In most cases, these kidney lesions develop from innate toxicity of these medications, but underlying host risk factors and the renal handling of these drugs clearly increase the likelihood of nephrotoxicity. This article reviews some of the classic nephrotoxic chemotherapeutic agents and focuses on examples of the clinical and histopathologic kidney lesions they cause as well as measures that may prevent or treat drug-induced nephrotoxicity.

Bisphosphonate nephrotoxicity

Bisphosphonates are valuable agents for the treatment of post-menopausal osteoporosis (PMO), hypercalcemia of malignancy, and osteolytic bone metastases. Oral bisphosphonates are used mainly to treat PMO and are not associated with significant nephrotoxicity. In contrast, nephrotoxicity is a significant potential limiting factor to the use of intravenous (IV) bisphosphonates, and the nephrotoxicity is both dose-dependent and infusion time-dependent. The two main IV bisphosphonates available to treat hypercalcemia of malignancy and osteolytic bone disease in the United States are zoledronate and pamidronate. Patterns of nephrotoxicity described with these agents include toxic acute tubular necrosis and collapsing focal segmental glomerulosclerosis, respectively. With both of these agents, severe nephrotoxicity can be largely avoided by stringent adherence to guidelines for monitoring serum creatinine prior to each treatment, temporarily withholding therapy in the setting of renal insufficiency, and adjusting doses in patients with pre-existing chronic kidney disease. In patients with PMO, zoledronate and pamidronate are associated with significantly less nephrotoxicity, which undoubtedly relates to the lower doses and longer dosing intervals employed for this indication. Ibandronate is approved in the US for treatment of PMO and in Europe for treatment of PMO and malignancy-associated bone disease. Available data suggest that ibandronate has a safe renal profile without evidence of nephrotoxicity, even in patients with abnormal baseline kidney function.

Podocyte injury associated glomerulopathies induced by pamidronate

BACKGROUND

Pamidronate has been demonstrated to decrease bone-related complications in multiple myeloma and delay progression of the disease. This has led to its use in supportive and maintenance therapy of myeloma in conjunction with steroids and chemotherapy. It has also been selectively used in patients with breast cancer and other neoplasms.

METHODS

We report on five patients who developed glomerular disease induced by pamidronate. Pamidronate was the only drug common to all patients. Tests for hepatitis B and C and human immunodeficiency virus (HIV) were negative for all patients. The first two patients received a high dose of pamidronate for 8 weeks, whereas the other three patients were on monthly therapy for a prolonged period of time. Sources of data included chart review and pathologic analysis of kidney biopsy.

RESULTS

Three patients were female and two were males and all were Caucasian, ranging in age from 58 to 71 years. Renal biopsy findings included minimal change disease in two, focal segmental glomerulosclerosis in two, and collapsing focal segmental glomerulosclerosis in one. Immunofluorescence was essentially negative in all cases. Electron microscopy showed variable podocyte injury and extensive foot process effacement. There was no evidence of multiple myeloma-related renal disease. After the biopsy, pamidronate was discontinued and renal function stabilized in all patients except the one with the collapsing variant of focal segmental glomerulosclerosis who required hemodialysis. Three patients had resolution of proteinuria, one patient continued to have proteinuria without deterioration in renal function.

CONCLUSION

Pamidronate has been mainly associated with collapsing focal segmental glomerulosclerosis. This report expands that relationship and adds other glomerular diseases linked with podocyte injury. Additional studies are needed to define the cause of the variability of renal histology with this agent.

Dosing time-dependent nephrotoxicity of cyclosporin A during 21-day administration to Wistar rats

The incidence of cyclosporine A (CsA) nephrotoxicity with reference to the temporal stage of administration was studied during a chronic 21-day treatment in male Wistar rats. Oral administration (20 mg/kg/day) was given at four different times: 1, 7, 13, or 19 hours after light onset (HALO). Plasma creatinine and blood urea nitrogen (BUN) levels were determined at regular intervals over the 24 h: before treatment (day 0); 7, 14, and 21 days after the beginning of treatment (days 7, 14, and 21); and 7 and 14 days after CsA withdrawal (days 28 and 35). At the same times, creatinine clearance and g-glutamyl transferase urinary excretion were determined in the groups of animals treated at 7 and 19 HALO. Residual concentrations of CsA in the renal tissue were measured at the end of the treatment period (day 21) in all groups. Nephrotoxicity of CsA was dependent on the temporal stage of administration. The renal vasoconstriction showed by the increase in plasma creatinine and BUN levels and the decrease in creatinine clearance was maximal when the CsA was given at 7 and 19 HALO and was correlated to the tissue concentrations of CsA. Tubular injury seems to occur earlier and the return to normal function less rapidly in animals treated at 19 HALO compared with animals treated at 7 HALO.

Day time and night time effects of 24R,25-dihydroxycholecalciferol on renal alkaline phosphatase and gamma-glutamyltransferase activities in intact rats

The effects of 24R,25-dihydroxycholecalciferol [24,25(OH)2 CC] on alkaline phosphatase (APA), gamma-glutamyltransferase (gamma-GT) and acid phosphatase (AP) activities were investigated on renal cortex slices of intact rats killed at 18h00 or at 06h00. At 06h00, three, six and nine hours after a single intraperitoneal injection of 24,25(OH)2 CC, APA activity was increased by 30%, 51% and 29%, respectively and gamma-GT activity, by 25%, 39% and 38%, as compared to their controls. AP on the other hand was not modified at all. These enzymatic stimulations were statistically higher than those measured at 18h00, respectively APA: 11%, 25%, 28% and gamma-GT: 2%, 20%, 22%. They can be explained by variations in new protein synthesis in relation with rat activity periods. Physiological significance of these renal effects remains to be elaborated.

Development of renal toxicity in F344 rats gavaged with mercuric chloride for 2 weeks, or 2, 4, 6, 15, and 24 months

Both sexes of F344 rats were gavaged with maximal tolerated doses of mercuric chloride for periods from 2 wk to up to 2 yr to investigate chronic nephrotoxicity and potential carcinogenicity. The toxicity of mercuric chloride was excessive after 2 wk of exposure to doses ranging from 1.25 to 20 mg/kg, compromising renal function by selectively destroying cells of the proximal tubules, and eliciting marked elevations in urinary biomarker enzymes diagnostic for acute renal tubule necrosis. In the 2-wk studies, urinary alkaline phosphatase and aspartate amino-transferase were most sensitive to renal mercury toxicity among a panel of six enzymes, exhibiting twofold increases above controls at the 5.0 mg/kg dose, before changes in the other enzymes occurred. Urinary lactate dehydrogenase was the most responsive enzyme, with up to 11-fold increases in activity above controls. In response to mercuric chloride exposure of 5.0 mg/kg for 2-6 mo, the greatest and most persistent increases in elevation of urinary enzyme activities were exhibited by alkaline phosphatase and gamma-glutamyl transferase, which increased two-to threefold above controls. At this interval, the maximal severity of the renal lesions in both sexes of rats was graded as minimal to mild. Beyond 6 mo none of the urinary enzymes measured in this study was adequate as biomarkers of nephrotoxicity, although the severity of the renal lesions had progressed. Mercury accumulated in a dose-related fashion primarily in the kidney, and to a lesser extent in the liver. The severity of the renal lesions was increased by continued exposure to mercuric chloride, as tissue concentrations of mercury rose in proportion to dose. Mercuric chloride treatment for 2 yr clearly exacerbated the severity of the spontaneous nephrotoxicity prevalent in aging F344 rats. The excessive mortality that occurred in the male rats was probably due to a combination of these factors. No renal tumors were detected in rats, possibly because the potential for their development was reduced; however, direct tissue contact with mercury induced squamous-cell papillomas of the forestomach in both sexes.

Excretion of urinary enzymes in female Sprague-Dawley rats in relation to cellular compartment, creatinine excretion and diuresis

One hundred and one young-adult female Sprague-Dawley rats were acclimatized to metabolic cages for 2 days. After that time 24-hour urine was collected at a constant cooling temperature of 0-4 degrees C. After gel filtration the enzyme activities were determined, and the resulting values were used to calculate 24-hour excretions. The following reference ranges (2.5 and 97.5 percentiles) were determined (in mU/24 h): lactate dehydrogenase 43-181; phosphohexoseisomerase 45-1445; glutathione-S-transferase 1-299; alkaline phosphatase 27-1239; leucine arylamidase 72-377; gamma-glutamyltransferase 1334-9188; arylsulphatase A 59-309; beta-galactosidase 76-305; beta-glucuronidase 20-2756; beta-N-acetyl-D-glucosaminidase 66-491; glutamate dehydrogenase 7-711. There was a significant (though not very high) correlation with diuresis for the lysosomal enzymes beta-N-acetyl-D-glucosaminidase, arylsulphatase A and beta-galactosidase, and for glutamate dehydrogenase, lactate dehydrogenase, phosphohexoseisomerase and alkaline phosphatase. The relation to creatinine excretion was markedly close for the lysosomal enzymes beta-N-acetyl-D-glucosaminidase, arylsulphatase A and beta-galactosidase (r = 0.71-0.83), as well as for alkaline phosphatase, leucine arylamidase and gamma-glutamyltransferase. There was a relatively high correlation between the excretion of beta-N-acetyl-D-glucosaminidase, arylsulphatase A and beta-galactosidase among themselves (r = 0.63-0.81) as well as between leucine arylamidase and gamma-glutamyltransferase (r = 0.75).

Disposition and nephrotoxicity of 3-amino-1-hydroxypropylidene-1,1-bisphosphonate (APD), in rats and mice

The purpose of this study was to investigate the disposition and the nephrotoxicity of 3-amino-1-hydroxypropylidene-1, 1-bisphosphonate (APD-pamidronate) in order to elucidate the mechanism of the non-linearity of the renal elimination of this drug. The fate of APD labelled with [14C]APD was studied in mice and rats for a range of doses (0.5-40 mg/kg) and indicators of renal function were monitored. In both species, the percentage of dose excreted during the first 24-h after treatment fell dramatically as a function of the dose. However, the renal burden of APD rose linearly for doses of APD below 10 mg/kg and increased non-linearly over this threshold. In contrast the concentration of APD in both bone and liver, which together account for a large proportion of the dose, appeared to increase proportionally with dose. There was no evidence, therefore, that the non-linear renal elimination of APD was due to an increased uptake of APD by tissues. Conversely, the significant fall in the renal excretion of APD was paralleled by a striking loss in body weight, and for high doses, by a fall in the creatinine clearance. An increased enzymuria suggested the loss of brush border membranes and the release of lysosomal contents by proximal tubular cells. Morphological studies confirmed this and revealed a focal proximal tubular necrosis 6 days post dosing. We conclude that the nephrotoxicity of APD accounts for the non-linear renal elimination of this drug.

Nephrotoxicity screening in rats; general approach and establishment of test criteria

The concept of a nephrotoxicity screening test that is based on quantitative assessment of urine collected under standardized conditions for 15.5 h is presented. One to eight urine collections were performed in large numbers of untreated female Sprague-Dawley rats. Normal values for water consumption, urine volume, pH, and excretion of protein, gamma-glutamyltranspeptidase, malate dehydrogenase, electrolytes, glucose, amino acids, leukocytes, erythrocytes, epithelia, unspecified cells and cylinders were determined. Test criteria were established based on the statistical distribution of these measurements. In rats repeatedly placed in metabolism cages, a statistically significant decrease in leukocyte excretion and an increase in excretion of epithelia and unspecified cells were observed. All other variables did not change with time.

Comparison of the protection given by selenite, selenomethionine and biological selenium against the renotoxicity of mercury

The protective effect of selenite, seleno-dl-methionine and biological selenium against the renotoxicity of mercury was tested in rats. As the source of biological selenium, the liver soluble fraction of rats given 60 mumoles/kg selenite 3 days before sacrifice was used. The aim of the experiments was to test whether protective efficiency follows the reported order of ability to form HgSe. Mercury was given subcutaneously in doses of 2.5, 5.0 and 7.5 mumoles/kg HgCl2 and selenium was given in equimolar doses at the same time as Hg2+. Liver soluble fraction, biological selenium or liver soluble fraction supplemented with selenite or seleno-dl-methionine were given orally, while in experiments without liver soluble fraction the two selenium compounds were given subcutaneously. Biological selenium was tested only at the two lower dose levels. Both biological selenium and seleno-dl-methionine decreased the urinary excretion of mercury in the first 48 h, but less so than selenite and only selenite decreased the renal content of mercury at the end of this period. Urinary alkaline phosphatase activity and plasma urea nitrogen at the 2.5 and 5.0 mumoles/kg dose levels decreased in the order of no selenium greater than biological selenium greater than seleno-dl-methionine greater than selenite. As the reported HgSe formation increases in the same order, the experiments support the role of HgSe formation in the protective effect. The degree of necrotic damage in the P2 and P3 regions of the proximal tubular cells increased in the same order as the biochemical indicators at the 5.0 and 7.5 mumoles/kg dose levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian rhythm in gamma glutamyltranspeptidase and leucine aminopeptidase urinary activity in rats

Urinary gamma glutamyltranspeptidase (GGT) and leucine aminopeptidase (LAP), renal tubular brush border enzymes, have been shown to be sensitive indicators of renal tubular functions. This study documents circadian rhythms in the urinary activity of GGT and LAP, statistically validated and quantified by the cosinor method, in 15 male Wistar rats standardized to a LD 12:12 illumination schedule (light from 0800 hr to 2000 hr) and fed ad libitum. The acrophase of the circadian rhythms in urinary GGT and LAP activity occurred at the end of the rest span of the animals: between 1730 and 1915 for GGT (depending on the mode of expression of the activity) and between 1700 and 1910 for LAP. Of striking resemblance in their timing, both these rhythms were also of large amplitude (about 50% of the mesor for urinary GGT activity and about 45% for LAP one). The circadian acrophases of urinary GGT and LAP activity led in timing the circadian rhythms in urine volume and creatinine excretion by about 13 hr. Such findings consistent with the circadian variations found by other investigators in GGT in kidney homogenates or in LAP in human urine thus reflect a periodicity in renal tubular function. The reasons for these circadian variations, still unknown at this time, are discussed. The influence recently demonstrated of the hormonal context on protein and enzyme synthesis at the tubule, and its phase relations to urinary enzyme excretion emphasize how much the circadian rhythm in urinary GGT and LAP activity is well included in the murine time structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Kidney concentrations and urinary excretion of mercury, zinc and copper following the administration of mercuric chloride and sodium selenite to rats

The effect of single (SC) administration of mercuric chloride (1 mg Hg/kg) alone or jointly with (PO) sodium selenite (0.39 mg Se/kg) on kidney disposition of mercury (Hg) and metallothionein (MT) and urinary excretion of Hg, zinc (Zn) and copper (Cu) has been studied in the female rat. The excretion of Hg and essential metals was determined every day following exposure. Daily excretion of endogenous Cu and Zn the Hg-exposed group was about threefold and fourfold, respectively, in comparison with control groups of rats. Sodium selenite prevented the urinary excretion of endogenous Cu and partly of Zn.

Increased nephrotoxicity of gentamicin in pyelonephritic rats

Multiple factors may increase the nephrotoxic potential of aminoglycosides. We studied gentamicin susceptibility of kidneys infected with E. coli. Several parameters of renal function, histological changes on light and electron microscopy, and drug levels in renal parenchyma were compared in pyelonephritic and normal rats treated with low doses (10 mg/kg/Q8 hr for 3 days), or high doses (60 mg/kg/day for 14 days), of gentamicin. A significant increase (P less than 0.01) in beta-galactosidase and protein excreted in urine over a period of 17 days associated with severe changes in diuresis and osmolality was noted in the infected treated rats (low doses) compared with normal, treated, infected or control animals. Histological modifications compatible with gentamicin nephrotoxicity were more persistent in the infected treated animals. A significant decrease in 14C inulin (P less than 0.01) and 3H-PAH clearance and secretion (P less than 0.02) was observed in the infected treated rats receiving high doses of antibiotics. Cellular necrosis and tubular desquamation also were more severe in this group. Gentamicin levels in the cortex and medulla of infected animals were significantly higher than in the normals (P less than 0.01) and might have been responsible for the increased toxicity noted in the pyelonephritic animals. Infected kidneys appeared to be more susceptible to the nephrotoxic potential of gentamicin.

Early biochemical effects of an organic mercury fungicide on infants: "dose makes the poison"

Phenylmercury absorbed through the skin from contaminated diapers affected urinary excretion in infants in Buenos Aires. The effects were reversible and quantitatively related to the concentration of urinary mercury. Excretion of gamma-glutamyl transpeptidase, an enzyme in the brush borders of renal tubular cells, increased in a dose-dependent manner when mercury excretion exceeded a "threshold" value. Urine volume also increased but at a higher threshold with respect to mercury. The results support the threshold concept of the systemic toxicity of metals. gamma-Glutamyl transpeptidase is a useful and sensitive marker for preclinical effects of toxic metals.

Application of whole-body autoradiography in toxicology

Whole-body autoradiography enables the drugs and toxicants to be distributed throughout the animal. Good results are obtained with this technique. However, certain artifacts can occur that could lead to misinterpretation, and these must be known. These artifacts are described. From the metabolic point of view, autoradiography provides data on the distribution kinetics of a compound and the elimination of radioactivity in various organs. These data are a guide for quantitative research into the metabolism of a compound. From the toxicological point of view, it must be admitted that the main purpose of this technique is to reveal the sites of retention of radioactivity. Such specific organ retention could be the consequence of the activation of a minor metabolite into a very reactive compound. If this is so, it is a specific organ effect which could not be studied by other techniques and could lead the way to a more specific organ effect which could not be studied by other techniques and could lead the way to a more appropriate line of research in the study of chronic toxicity. However, it must be recalled that the fact that a compound is retained by a specific organ does not always mean that the compound exerts a toxic effect upon the said organ. With this technique, distribution study can be performed on pregnant animals, and it provides us with more data concerning the transplacental passage of radioactive metabolites. All these aspects of the technique clearly indicate that whole-body autoradiography should be insisted upon during the early stages of development of new molecules. Successive experiments could then lead to selecting the best experimental conditions for metabolic pharmacokinetics and studies in toxicology.

Inhibition of the enzymes of glutathione metabolism by mercuric chloride in the rat kidney: reversal by selenium

The treatment of rats with 10 mumoles/kg (s.c.) of mercuric chloride (Hg2+) caused time-dependent decreases in the activities of the enzymes of the glutathione (GSH) metabolism pathway in the kidney. Twenty-four hours after administration of Hg2+, the activities of gamma-glutamylcysteine synthetase and glutathione disulfide (GSSG)-reductase in the kidney were decreased by 50-60%, and the activities of the GSH catabolic enzymes, gamma-glutamyl transpeptidase and GSH-peroxidase, were decreased by 25-35%. In the liver, only the activity of GSSG-reductase was decreased at this time. The observed decreases in the enzyme activities were not accompanied by a depression in the cellular protein concentration. The same pattern of enzyme response was noted when rats were given 30 mumoles/kg Hg2+; however, the decreases in the specific activity of the enzymes were accompanied by great losses in the cellular protein concentrations in both the liver and the kidney (35-40%). This dose of Hg2+ also caused significant decreases in the concentration of GSH in both organs. In vitro, Hg2+ only inhibited the activity of GSSG-reductase. When rats were given sodium selenite (Na2SeO3; 5, 10 or 20 mumoles/kg, s.c.) 30 min after Hg2+ treatment (10 mumoles/kg), the Hg2+-related depressions in the activities of the enzymes of GSH metabolism in the liver and the kidney were blocked. Also, in rats treated with 30 mumoles/kg Hg2+, the administration of 10 mumoles/kg selenium significantly decreased the magnitude of depression in the concentration of GSH in the kidney.

Protection against mercuric chloride nephrotoxicity by cold exposure in rats

The influence of cold exposure (+ 1 degree C for 24 h) was studied in rats dosed i.p. with 0, 2.5 or 5.0 mumol HgCl2/kg. Cold exposure of controls caused an increased diuresis and solute elimination, except sodium, with almost no variations in urine alkaline phosphatase (ALP) and gammaglutamyl transferase (GGT). Proximal tubule brush border damage was demonstrated by a marked increase in ALP and GGT in HgCl2-dose animals at room temperature. Cold exposure protected against this kidney damage.

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.

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.

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.

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.

Methoxyethylmercury nephrotoxicity: effects on enzymuria and kidney function

The fungicide, methoxyethylmercury chloride, was given in a saline solution to four groups of Sprague-Dawley C D rats (5 male, 5 female) as a single injection (IP) of 0, 0.5, 1.0, and 2.0 mg Hg/kg. In a three-day period, no changes were observed in urine collected every 24 h from rats given 0 or 0.5 mg Hg/kg; 1 mg Hg/kg induced only a transient increase of urine gamma glutamyl transferase (x 4) and alkaline phsophatase (x 2.5) on the day 2; 2.0 mg Hg/kg caused an early increase of enzymuria (day 1 and day 2) and a decrease of Na+, Cl-, K+, urea, and creatinin excretion. Urine enzymes and total mercury excretion were higher in males. These time-related variations of enzymuria, compared to previous results with Hg Cl2, could reflect the existence of metabolites more toxic than the native compound.

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.