Renal Failure, 14(3), 31 1-319 (1992)

Glutathione and Glycine in Acute Renal Failure

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

Joel M. Weinberg Division of Nephmlogy, Department of Internal Medicine University of Michigan and Veteran's Administration Medical Center Ann Arbor, Michigan

ABSTRACT

Glutathione is an important intracellular antioxidant in virtually all tissues, including the kidney. In the kidney, it has a rapid turnover in tubule cells and likely plays a role in any oxidant-related events which contribute to the tubule cell injury which occurs during acute renal failure. It was surprising, therefore, to find that the component amino acid, glycine, rather than glutathione itself, most strongly modulated the sensitivity of tubules cells to a variery of insults in several in vitro systems where rhese processes can be studied most directly. lhis paper reviews available evidence concerning the nature of both glutathione and glycine efects, their expression in vivo in in vitro, and their implications for understandng acute renal failure.

The low molecular weight sulfhydryl-containingtripeptide which would become known as glutathione was first recognized in yeast in 1888 by de Rey-Pailhade and its tripeptide structure was firmly established during the 1920s (1). It is the most abundant nonprotein thiol in cells, with concentrations which are usually in the 1-10 mM range ( 1 , 2). Glutathione's component amino acids are glutamate, cysteine, and glycine. The cysteine, which contains the SH group that confers much of the biological activity of the molecule, is linked by a standard peptide bond to glycine and to the y-carbon of glutamate, a feature which provides additional specificity utilized by cells in processing the molecule (2).

Intracellular glutathione metabolism has been extensively studied, particularly in the liver and kidney which together largely account for the disposition of circulating glutathione (2-7). The proximal tubule cell metabolism of glutathione which comprises most of its renal handling was largely worked out during the 1970s by a number of laboratories (2, 4-16) although there remain areas of uncertainty and controversy. The most important feature of the process for understanding the behavior of glutathione during ischemic acute renal failure is that the mpeptide turns over rapidly and potentially constantly cycles in and out of the cell. Filtered glutathione is metabolized by y-glutamyl transpeptidase to glutamate and cysteinylglycine. The cysteinylglycine is further hydrolyzed to 311

Copyright 0 1992 by Marcel Dekker, Inc.

Weinberg

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

312

the component amino acids by either of at least two other brush-border ectoenzymes, aminopeptidase N or dipeptidase. The free amino acids as well as cysteinylglycine are all readily transported into the cell where they can be used for resynthesis of glutathione. Both unique steps of glutathionesynthesis, formation of y-glutamyclsysteine by y-glutamylcysteine synthetase and formation of glutathione by glutathione synthetase, are ATP dependent. Many of the important intracellular reactions involving glutathione result in its oxidation to the disulfide, GSSG (17). GSSG can be returned to the reduced form by glutathione reductase which uses NADPH as the hydrogen donor ( 18). As an alternative to being metabolized in the cell, both GSH and GSSG can be exported for further metabolism by the same lumenal enzymes as filtered GSH. In addition to the apical processing of glutathione, there is a well-characterized, basolateral, Na+-linked transporter for intact glutathione (19). The k, for this transporter is in the millimolar range which is much higher than the 10-20 ,uh4 circulating levels of glutathione. Although this makes its contribution to glutathione handling in vivo uncertain, there are data suggesting that it functions in vivo ( 5 )and its is potentially important in the interpretation of in vifrostudies of glutathione effects on injury. There is also basolateral y-glutamyltranspeptidaseactivity which can catabolize both GSH and GSSG (20-22) as well as thiol oxidase activity which appears to be predominantly basolateral (23). GSSG is a substrate for y-glutamyltranspeptidase with formation of all the expected disulfide derivatives that can in turn be either further broken down to the constitutent amino acids or transported intact and thus return to the cycle (10). Specific and potent inhibitors have been defined for several of the key steps of glutathione metabolism. They have been valuable for understanding the role of glutathione in cellular pathophy siology . y-Glutamyl transpeptidase is inhibited by Acivicin, thus preventing extracellular glutathione breakdown to its component amino acids (20,24). There are also less specific inhibitors such as serine borate (10) which are not as useful. Meister and co-workers developed a very effective and widely used inhibitor of y-glutamylcysteine synthetase, buthionine sulfoximine (25). Glutathione peroxidase, which catalyzes the reduction of hydrogen peroxide by glutathione, is a selenium-dependent enzyme which can be markedly reduced by dietary selenium deficiency (26). Glutathione reductase, which uses NADPH to reform

+

GSH from GSSG, is very potently inhibited by bischloroethylnitrosourea (BCNU) (27). Glutathione plays a role in several major processes that can contribute to cell injury. The reduction of hydrogen peroxide and other low molecular weight peroxides in cellular aqueous compartments by glutathione peroxidase will decrease free radical-mediated damage (17,28,29). Glutathione can limit lipid peroxidation by reducing lipid hydroperoxides in membranes using an a-tocopherolmediated mechanism and, possibly, by direct interaction (30-32). The tripeptide can limit accumulation of protein disulfides by reacting with the oxidants that induce them as well as directly with the protein targets (33). Conjugation with glutathionemediated by glutathione-S-transferase is used to detoxlfy multiple compounds but can, in some cases, also convert them to more toxic reactive intermediates (34, 35). The role played by intracellular glutathione in protection against cell injury has been extensively studied for insults involving strong oxidant challenges or formation of reactive metabolites (33, 36, 37). Most of this work has been done in liver; however, it is clear that the same processes are expressed in the renal tubular epithelium. Tubular lesions in which central pathogenetic roles for glutathione alterations have been suggested include those produced by actetaminophen (38), ally1 alcohol (39), fenbutylhydroperoxide(40-43), bromobenzene (U),cysteine conjugates (43), and cephalosporins (45). Involvement of glutathione in ischemic injury has been receiving more attention lately because of interest in oxidant mediators of that process (46-48). Its role remains incompletely defined. Moreover, it has led to recognition of another unexpected process which has been our major interest in the area. We have studied actions of glutathione directly at the tubule cell level by testing the effect of glutathione supplementation in a well-defined model of hypoxic injury to isolated rabbit proximal tubules in suspension (49). GSH, added to either hypoxic or oxygenated tubules, was rapidly degraded to its component amino acids (50). This is consistent with the well-defined surface enzymes for glutathione catabolism in proximal tubules. In our initial studies of the ability of glutathione supplementation to alter the response to hypoxia, we assessed cell respiration, ATP levels, K+ content, and protein recovery after centrifugation through oil in tubules that were subjected to 30 min of hypoxia and 60 min of reoxygenation. When measured at this time point, all of these parameters reflect the extent of lethal cell injury as shown in Figure 1, which summarizes the results of a subsequent

Glutathione and Glycine in ARF

313

CELL K+

BASAL RR Y

3 8 .

-I

a 100 E Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

L

.-

E

2 0 0

E

50 25

--

0

0

80 Y

50

---

0 ,

I

1

I

I

60

I 8

__

--

40

--

20

--

0

I

I

I

i

y,0 *FKw 0

0

$ 0

I 0 I I

lDt0 .

0 0

Ir

1

I

I

Figure 1. Relationships between various metabolic parameters of injury and LDH release. Each point indicates a single tubule subjected to hypoxia + 60 min reoxygenation or to control incubation. Degrees of injury in the hypoxic tubules were varied by altering the duration of hypoxia or adding glycine or reducing the medium pH. Basal and carbonyl cyanide-m-chlorophenylhydrazone-stimulated(CCCP) respiratory rates were determined polarographically. Cell K + was determined on tubules separated from medium by centrifugation through bromododecane. Protein recovery is the percent of suspension protein recovered during that centrifugation procedure. Cell ATP, not illustrated, behaved similarly to cell K + . Detailed methods used for these studies have been published previously (50, 51). The data have not been previously reported.

study where we correlated their values across a wide spectrum of tubule cell injury with LDH release, a wellaccepted quantitative index of lytic cell damage that we have used for all of our recent work. Supplementing the tubules with GSH was highly beneficial. Figure 2 shows tubule respiratory rates. In untreated tubules, both basal and uncoupler-stimulated respiration were markedly reduced compared to control values as a result of extensive loss of viability. Glutathione restored these values to their control levels but so did either the combination of the three glutathione amino acids, cysteine, glutamate, and glycine, or glycine alone. Cysteine and glutamate alone were not effective (50). Cell K + , ATP, and protein recovery behaved similarly (50). To further characterize this effect, we assessed the time course of hypoxic injury and its modification by either glutathione or glycine without a period of reoxygenation. Tubules showed progressive injury, quantified as release of lactate dehydrogenase, for up to 60 min of hypoxia. This injury was completely suppressed by inclusion of either glutathione or glycine in the incubation medium (51). Similar protection by both glutathione and glycine

0BASAL RR

eZa

CCCLP RR

. I .

**

*.

. I

tl

I

Figure 2. Tubule respiratory rates following 30 min hypoxia + 60 min reoxygenation with no further additions to the basic incubation medium (HYPOXIA), 2 mM GSH, 2 mM cysteine + 2 mM glycine + 2 mMglutamate (CGG), 2 mMglycine (GLY), 2 mMcysteine (CYS). 2 mM glutamate (GLU). Time controls were oxygenated throughout (CONTROL). Valuesare means f SE for 5-7 experiments. **p < .01, ***p < ,001 vs. paired no further addition HYPOXIA tubules. Figure redrawn from Ref. 50.

Weinberg

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

314

was found during exposure of the cells to a variety of inhibitors of mitochondrial oxidative phosphorylation including the electron transport blockers antimycin and cyanide, the proton ATPase inhibitor oligomycin, and the uncoupler carbonyl cyanide-rn-chlorophenylhydrazone (52). Supplementation of control, oxygenated tubules with either glutathioneor the glutathioneamino acids, increased intracellular glutathione levels. Supplementation with glycine alone did not affect intracellular glutathione levels (50, 5 1). Intracellular glutathione fell during hypoxia irrespective of the presence of glutathione in the medium, but the preincubation with glutathione used in these studies maintained higher intracellular glutathione levels in the treated tubules throughout the period we assessed. Glycine had a lesser but still significant effect to preserve intracellular glutathione (51). Similar effects were found with the metabolic inhibitors. In each case, metabolic inhibition was accompanied by loss of glutathione, while protection by glutahone or glycine was associated with slight but significant amelioration of this loss (52). These glutarhione measurements represent predominantly GSH. The sensitivity of our assay was not sufficient to precisely quantify GSSG in the amounts of material available from our tubule samples, but we were able to establish that in excess of 98% of the glutathione measured was in the reduced form. To determine whether the increment of glutathione observed in the protected cells was a cause of protection or simply a consequence of maintenance of cell integrity, we used glutathione-depleting agents. In our first study, tubules were treated with either no further additions, with GSH, or with GSH plus buthionine sulfoxamine for either 45 min under oxygenated conditions, or for 15 min of oxygenation followed by 30 min of hypoxia. Cellular glutathione decreased during hypoxia in both the absence and presence of glutathione. GSH-supplemented tubules, however, had much higher glutathione levels at both points. Buthionine sulfoximine not only prevented these increases of cellular glutathione induced by GSH supplementationbut lowered cellular glutathione to below the levels seen in untreated hypoxic tubules. In spite of this lowering of cell glutathione, protection by exogenous GSH was completely preserved in the presence of buthionine sulfoximine. Groups treated with GSH alone buthionine sulfoximine showed the same and GSH degree of nearly complete protection despite a greater than 15-fold difference in their cellular glutathione contents (51). The role of preservation of intracellular during hypoxia was also tested using BCNU to inhibit glutathione

+

reductase and glycine as the protective agent. In oxygenated tubules, BCNU lowered tubule cell glutathione to less than 10%of control values and induced mild damage, which was not amelioratd by glycine. In hypoxic tubules, BCNU further lowered cell glutathione, although it did not potentiate injury. Glycine did not alter the effect of BCNU on cell glutathione but had a typical strong protective effect (51). Very similar results were seen when tubules injured by rotenone were studied in the presence of buthionine sulfoximine, BCNU, glycine, and GSH (52). Possibly the most dramatic dissociations between cellular glutathione status and hypoxic injury were seen in studies with the potent alkylating agent iodoacetate, which inhibits both glycolysis and mitochondrial oxidative phosphorylation and profoundly depletes intracellular glutathione (Fig. 3). Cellular glutathione in iodoacetatetreated tubules was decreased to less than 2 % of normal values under both control and hypoxic conditions, yet protective effects of glycine were maintained against both the toxicity of iodoacetateand the damage seen by iodoacetate and hypoxia combined (65). These results indicate that: (a) intrinsic acute tubule susceptibility to damage from hypoxia and related forms of ATP depletion is not substantially modulated by the cell’s glutathione status, and (b) the glycine moiety of glutathione under these conditions is the protective factor. We are currently devoting most of our investigative efforts to studying this effect of glycine. It is expressed in proximal tubule cells (50-54), the medullary thick ascending limb (55, 56), and MDCK and LLC-PK, cells (57), as well as in hepatocytes (58, 59) and endothelial cells (60). The effects are not limited to glycine but are nonetheless highly specific. Other amino acids for which this effect is consistently demonstrable are L- and D-alanine, 0alanine, and 1-aminocyclopropane-1-carboxylate (54-58, 60-62). It is also seen in a more variable fashion with aminoisobutyricacid, and L- and D-serine, depending on cell type and species (57, 60, 63). The effect is distal to several of the major pathophysiological processes considered important during injury. These include the changes of glutathione detailed previously, severe depletion of cell ATP (51, 52), and large increases of cytosolic free calcium (57, 60, 64). It is evident with a variety of insults, but not necessarily all forms of damage. There is activity during injury secondary to hypoxia (50, 51, 53, 54, 61), ATP-depleting metabolic inhibitors (52, 59,64,65), ouabain (66), Ca2+ ionophore (64), Ca2+ depletion (67), and to rewarming after cold preservation (58). Studies thus far have shown

Glutathione and Glycine in ARF

315

0- GLY a + GLY 6 t

1

02

02 IAA

HYPOX

HYPOX IA4

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

80

I

9

'

L

60

W

Iz W

T 40

0

IL:

k!

I

20

0

a 02

02 IA4

HYPOX

HYPOX IAA

Figure 3. Glutathione levels and LDH release of hypoxic and oxygenated tubules treated with iodoacetate (IAA). Tubules were incubated for 45 min under oxygenated conditions ( 0 2or ) for 15 min under oxygenated conditions followed by 30 min of hypoxia (HYPOX) without or with I mM IAA. Values are means f SE for 4 experiments. Glutathione levels with IAA were significantly less than those without in all groups ( p < .01) and were not altered by glycine except in hypoxic tubules not treated with IAA. LDH release with glycine was less than without glycine in all groups ( p < .01) except the oxygenated time controls. Drawn from data in Ref. 65.

relativley small or absent protection against damage by mercuric chloride (67), ten-butyl hydroperoxide (66), nystatin (68), and cell swelling induced by isotonic replacement of Na+ with K + (66). The focus of this article does not permit detailed consideration of all aspects of glycine protection; however, the behavior of intracellular glycine is particularly relevant to understanding expression of this phenomenon under various conditions. We measured glycine levels in freeze-clamped rabbit cortex of 67 nmol/mg protein (69). This is in excess of 20 mM but is compatible with the concentrative capacity of microperfused isolated rabbit tubules (70, 71). In rats, which have lower circulating glycine levels than rabbits, Duran et al. have reported cortical levels of 6.5 mM (72). Thus, cellular glycine is normally quite abundant in renal tubules in vivo. Isolated

rabbit tubules were depleted of virtually all their glycine. They had 2.1 nmol/mg protein at the end of the isolation procedure and glycine content did not recover during 90 min of incubation at 37 "C under control conditions (69). This was not due to nonspecific damage, since, under the same conditions, glutathione was less severely depleted during preparation and partially recovered during 37 "C incubation while ATP was only mildly reduced during the preparation and recovered fully (51). Cell K + which is lost during preparation also fully recovers (50, 73). When supplemented with glycine during 37°C incubation, the isolated tubules in suspension rapidly took up the amino acid. Addition of 2 mM glycine produced a stable intracellular level of 10 mM while 1.7 mM was left in the medium (69). Tubules treated with mitochondria1 inhibitors or ouabain failed to concentrate added glycine but did rapidly equilibrate their intracellular concentrations with whatever level was in the medium. If tubules were preloaded with glycine prior to addition of metabolic inhibitor they lost the actively concentrated portion of cell glycine but maintained intracellular levels similar to medium concentrations (69). These data show that cellular levels of glycine are quite labile. Protective effects of supplemental glycine are strongly expressed in the isolated tubule system as well as in most other in v i m preparations of susceptible cells because in v i m conditions virtually always favor glycine depletion, if not before the injurious state as in the tubules, then during it. The effect of glycine, therefore, must be considered constitutive; that is, it is probably normally present in vivo and, therefore, will not necessarily be subject to manipulation by supplementation under conditions where injury does not promote glycine depletion. One such setting is experimental ischemic acute renal failure during the clamp. There, active concentration of glycine and of alanine, the other protective amino acid which is relatively abundant in vivo, will be impaired by ATP depletion. But the tubule cells in vivo are rich in glycine and this glycine can leak only into a relatively small extracellular space. Thus, protective levels would be maintained. This may be a factor which contributes to the welldocumented resistance of tubule cells to lethal cell injury in vivo during the actual period of clamping (74,75). During the reflow period, however, loss of glycine and alanine from damaged cells could predispose them to go on to lethal cell injury. Duran et al. have reported a 50% decrease of cortical glycine and a 30% decrease of cortical alanine at 3 h postischemia (72). Although the levels remaining should still have been fully protective, injury in this setting is known to be quite heterogenous, so that some cells may have sustained more severe losses.

Weinberg

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

316

Thus, we believe that the degree to which cells will be amenable to protection by supplementation of amino acids above normal circulating levels will depend on several factors: (a) when the lethal hit actually occurs, because that is when the higher levels of amino acid must be delivered; (6) whether it can be delivered at that point; and ( c ) whether other effects of amino acids such as increasing workload, ammonia production, etc., are deleterious. All these issues remain to be explored. The limited published information from Zager on effects on infusion of glycine and alanine argue against efficacy in vivo and even suggests a certain level of toxicity (76,77); however, these studies were done before recognition of the protective actions of these agents and, thus, did not address the timing and concentration-dependentissues raised by the more recent observations. Additional studies will likely be forthcoming in the near future. There are also gaps in our understanding of the behavior and effects of glutathione during ischemic acute renal failure in vivo. McCoy et al. (78) reported that 40 min clamping of the renal artery resulted in a 39% decrease of total glutathione (which was 99 7% reduced) and a 59 % decrease of the much smaller amount of oxidized glutathione so that the glutathioneredox ratio fell from 1.09% to 0.67%.Five minutes of reperfusion, however, led to a sharp increase of oxidized glutathione while reduced glutathione remained the same so that the redox ratio transiently increased to 1.66%.It had returned to normal at 15 min. This transient increase of the redox ratio was significantly blunted by selenium deficiency-induced decreases of tissue glutathione peroxidase. Diquat, a known strong oxidant, produced an increase of the redox ratio similar to that seen during reperfusion although it was more sustained. The combination of BCNU diquat massively increased the redox ratio to 48 % . Tissue content of glutathione-protein mixed disulfides was decreased by about 50% during ischemia and recovered after ischemia but was slightly elevated only at 15 min of reflow in selenium deficient rats and in diquat-treated rats. The combination of BCNU plus diquat led to a massive increase of glutathione-protein mixed disulfides. Longer-term functional effects of these treatments were not assessed. Scaduto and co-workers (79) found a similar loss of glutathione during ischemia which was sustained during recovery. They showed that the glutathione was largely degraded to cysteine via a process which could be partially blocked by inhibition of ?-glutamyltranspeptidase with Acivicin. In contrast to the McCoy study, Scaduto’s group was unable to show increases of either oxidized glutathione or cysteine during reperfusion. They also did

+

not find any changes of glutathione mixed disulfides during ischemia. The cysteine formed from glutathione was washed out of the kidney with reperfusion. This was a limiting factor for recovery of tissue glutathione, because replacement of cy steine by treatment with N-acetylcy steine enhanced the recovery process (79). Linas and co-workers using isolated perfused kidneys following in vivo ischemia (80) or treated with a hydrogen peroxide-generating system (glucose glucose oxidase) (81) reported decreases of GSH that could be blocked by dimethylthiourea or, in the glucose glucose oxidase system, catalase. However, there were no accompanying increases of GSSG. Also of note, the protection provided by dimethylthiourea for the postischemic kidneys was lost at periods greater than 30 min even though DMTU still preserved GSH (80). From these observations it can be concluded that net breakdown of glutathione to its component amino acids with loss of the limiting amino acid cysteine is prominent during renal ischemia in vivo; however, changes in the glutathione redox state are small and transient. The latter effect may be due to either limited formation of oxidized glutathione or rapid catabolism. In either case, it is not maximally useful as index of oxidant stress in the kidney. With regard to studies which have manipulated glutathione levels during ischemia and assessed functional results, Paller has found that infusion of GSH 1 h before 60 min of clamp ischemia improved renal function measured at 24 h (82,83). Conversely, depletion of tissue glutathione with diethylmaleate aggravated the ischemic insult (82). The GSH treatment in this study was reported to increase tissue glutathione by 50%, while diethylmaleate decreased the glutathione levels fo 20% of control. These measurements are somewhat difficult to interpret, however, because they were done on kidneys that were perfused with iced saline for 8 min to clear the vascular space. The control glutathione levels reported were 1/2Oth those found in simple freezeclamped rat (79) and rabbit (51) cortex, and in glutathione-repleteisolated proximal tubules (51), so that there may have been considerable glutathione washout during tissue processing. Scaduto (84, 85) has reported studies where renal cortical glutathione levels were increased 2.5- to 5-fold by administration of glutathione monoethylester or were decreased to 18% of control by buthionine sulfoximine. The glutathione monoethylester induced vacuolization of control tubules and aggravated injury in the ischemic tubules. Buthinoine sulfoximine treatment did not affect the response to ischemia. Most recently, Nath and Paller (86) have shown striking aggravation of ischemic injury resulting from dietary

+ +

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

Glutathione and Glycine in ARF deficiency of both selenium (to inhibit glutathione peroxidase) and vitamin E. Which component of the dietary manipulation was most critical and the behavior of tissue glutathione were not reported. In conclusion, glutathione normally turns over very rapidly in renal tubule cells and its renal synthesis is ATP dependent so that changes of glutathione concentrations must be interpreted in the context of both alterations induced by participation in oxidant processes and the separate role of ATP depletion to reduce levels. In simple isolated tubule systems where mechanistic issues can be studied most directly, an antioxidant role for glutathione is well documented for several strong, chemical oxidant insults. Glutathione also has potent protective effects in hypoxic and other forms of isolated tubule injury induced by ATP depletion, but these are attributable primarily to effects of glycine under a variety of conditions thus far studied. The actions of glycine supplementation in vitro are not due to a supraphysiologicalor pharmacological action of the amino acid, but rather result from replacement of glycine to normal levels allowing restoration of a constitutive protective process that appears to be generalized for a number of tubule cell and other cell types and is applicable to a range of insults. Its mechanism is currently under detailed investigation. Tissue glutathione decreases during ischemia, probably because ATP depletion inhibits resynthesis. The extent and importanceof glutathioneoxidation during reoxygenation are unclear. Loss of cysteine formed from degradation during ischemia limits postischemic recovery of glutathione. The conditions and mechanisms by which in vivo infusion of glutathionecan beneficially affect the outcome of ischemic ARF remain to be more fully defined. Address correspondence and reprint requests to: Dr. Joel M. Weinberg, Nephrology Division, Room 1560, MSRB 11, University of Michigan Medical Center, AM Arbor, MI 481094676. The author’s work cited in this paper was supported by National Institutes of Health grants DK-34275, DK-39255, and DK-01337, the Department of Veteran’s Affairs, and the National Kidney Foundation of Michigan.

317 5 . Curthoys NP: Renal handling of glutathione. In Glurathione:

6. 7.

8.

9.

10.

11.

12.

13. 14.

15. 16.

17. 18.

19.

20.

21.

22.

REFERENCES Meister M: On the discovery of glutathione. TIBS 13:185-188, 1988. Meister A, Anderson ME: Glutathione. Annu Rev Biochem 52:711-760, 1983. Kaplowitz N, Aw TY, Ookhtens M: The regulation of hepatic glutathione. An Rev Pharmacol Toxicol 2:715-744, 1985. Mclntyre TM, Curthoys NP: The interorgan metbolism of glutathione. Inr J Biochem 12:545-551, 1980.

23.

24.

25.

Metabolism and Physiological Functims (edited by Vina J), p. 2 17. Boca Raton, FL, CRC Press, 1990. Meister A: Glutathione metabolism and its selective modification. J Biol Chem 263:17205-17208. 1988. Orrenius S, Ormstad K, Thor H, Jewel1 SA: Turnover and functions of glutathione studies with isolated hepatic and renal cells. Fed Proc 42:3177-3188, 1983. Griffth OW, Meister A: Translocation of intracellular glutathione to membrane-bound gamma-glutamyl transpeptidase as a discrete step in the gamma-glutamyl cycle: Glutathionuria after inhibition of transpeptidase. Proc Nail Acad Sci USA 76:268-272. 1979. Abbott WA, Bridges RJ, Meister A: Extracellular metabolism of glutathione accounts for its disappearance from the basolateral circulation of the kidney. J Biol Chem 259:15393-15400, 1984. Jones DP, Moldeus P, Stead AH, Ormstad K, Jornvall H, Orrenius S: Metabolism of glutathione and a glutathione conjugate by isolated kidney cells. J Biol Chem 254:2787-2792, 1979. Ormstad K, Jones DP, Orrenius S: Characteristics of glutathione biosynthesis by freshly isolated rat kidney cells. J Biol Chem 255:175-181, 1980. Sekura R, Meister A: Glutathione turnover in the kidney: considerations relating to the gamma-glutamyl cycle and the transport of amino acids. Proc Nail Acad Sci USA 71:2969-2972. 1974. Griffith OW: The role of glutathione turnover in the apparent renal secretion of cystine. J Biol Chem 256: 12263-12268, 1981. McIntyre T, Curthoys NP: Renal catabolism of glutathione. Characterization of a particulate rat renal dipeptidase that catalyzes the hydrolysis of cysteinylglycine. J Biol Chem 257:11915-1 1921, 1982. Kozak EM, Tate SS: Glutathionedegrading enzymes of microvillus membranes. J Biol Chem 257:6322-6327, 1982. Moldeus P, Ormstad K, Reed DJ: Turnover of cellular glutathione in isolated rat-kidney cells. Role of cystine and methionine. Eur J Biochem 116:13-16, 1981. Chance B, Sies H, Boveris A: Hydroperoxide metabolism in manmalian organs. Physiol Rev 59:527-605, 1979. Carlberg I, Mannervik B: Purification and characterization of the flavoenzyme glutathione reductase from rat liver. J Biol Chem 250:5475-5480, 1975. Lash LH, Jones DP: Renal glutathione trnasport. Characteristics of the sodiumdependent system in the basal-lateral membrane. J Biol Chem 259:14508-14514, 1984. Scott RD, Curthoys NP: Renal clearance of glutathione measured in rats pretreated with inhibitors of glutathione metabolism. Am J Physiol 252:F877-F882, 1987. Abbott WA, Bridges RJ, Meister A: Extracellular metabolism of glutathione accounts for its disappearance from the basolateral circulation of the kidney. J Biol Chem 259:15393-15400, 1984. Spater HW, Poruchynsky MS, Quintana N, Inoue M, Novikoff AB: Immunocytochemical localization of gamma-glutamyltransferase in rat kidney with protein A-horseradish peroxidase. Proc Nail Acad Sci USA 79:3547-3500, 1982. Lash LH, Jones DP, Orrenius S: The renal thiol (glutathione) oxidase subcellular localization and properties. Biochim Biophys Acta 779: 191-200, 1984. Capraro MA, Hughey RP: Use of acivicin in the determination of rate constants for turnover of rat renal gamma-glutamyltranspeptidase. J Biol Chem 260:3408-3412, 1985. Meister A: The rise and fall of cellular glutathione levels. Curr Top Cell Reg 26:383-394, 1985.

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

318 26. Burk RF: Molecular biology of selenium with implications for its metabolism. FASEB 5:2274-2279, 1991. 27. Babson JR, Reed DJ: Inactivation of glutathione reductase by 1-chloroethyl nitrosourn-derived isocyanates. Biochem Biophys Res Commun 83:754-762, 1978. 28. Freeman BA, Crapo JD: Biology of disease.Free radicals and tissue injury. Lab Inwsr 47:413-426, 1982. 29. Farber JL,Kyle ME, Coleman JB:Biology of disease.Mechanisms of cell injury by activated oxygen species. Lab Invesr 62:670-679, 1990. 30. Burk RF: Glutahionedependentprotection by rat liver microsomal protein against lipid peroxidation. Biochim Biophys Acta 757: 21-28, 1983. 31. Pascoe GA, Reed DJ: Cell calcium, vitamin E, and the thiol redox system in cytotoxicity. Free Rudic Biol Med 6:209-224, 1989. 32. Haenen GRMM, Bast A: Protection against lipid peroxidation by a microsornal glutathione-dependent labile factor. FEBS Lerr 159:24-28, 1983. 33. Bellomo G, Thor H, Onenius S: Modulation of cellular glutathione and protein thiol status during quinone metabolism. Meth Enzymol 186:627-634, 1990. 34. Pickett CB, Lu AYH: Glutathione S-transfemses: Gene structure, regulation, and biological function. Annu RevBiochem 58:743-764, 1989. 35. Monks TJ, Anders MW, Dekant W, Stevens JL, Lau SS, Van Bladeren PJ: Glutathione conjugate mediated toxicities. Toxicol Appl Pharmacd 106:l-19, 1990. 36. Reed DJ: Glutathione: Toxicological implications. Annu Rev PharI WZC O ~ TOX~CO~ 30:606-631, 1990. 37. Shan X, Aw TY. Jones DP: Glutathione-dependent protection against oxidative injury. P h u m c d 7her 47:61-71, 1990. 38. McMurtry RJ, Snodgrass WR, Mitchell JR: Renal necrosis, glutathione depletion, and covalent binding after acetaminophen. Toxicol Appl Phamcol46:87-100, 1978. 39. Ohno Y, Jones TW, Ormstad K: Ally1 alcohol toxicity in isolated renal epithelial cells: Protective effects of low molecular weight thiols. Chem Biol Inremcr 52:289-299, 1985. 40. Schnellmann RG: Mechanisms of r-butyl hydroperoxide-induced toxicity to rabbit renal proximal tubules. Am J Physiol 255: C28-C33, 1988. 41. Messana JM, Cieslinski DA. O’Connor RP, Humes HD: Glutathione protects against exogenous oxidant injury to rabbit renal proximal tubules. Am J Physiol255:F874-F884, 1988. 42. Hagen TM, Aw TY, Jones DP: Glutathione uptake and protection against oxidative injury in isolated kidney cells. Kidney Inr 34~74-81, 1988. 43. Hassall CD, Brendel K, Gandolfi AJ: Regulation of a S(rrans1,2-dichlorovinyl)-L-cysteine-inducedrenal tubular toxicity by glutathione. J Appl Toxicol 3:321-325, 1983. 44. Schnellmann RG, Mandel LI:Cellular toxicity of bromobenzene and bromobenzene metabolites to rabbit proximal tubules: The role and mechanism of 2-bmmohydroquinone.J P h a m c o l Exp 7h-r 237:456-461, 1986. 45. Kuo CH, Hook JB: Depletion of renal glutathione content and nephrotoxicity of cephaloridine in rabbits, rats, and mice. Toxicol Appl Pharmacol63:292-302, 1982. 46. McCord JM: oxygen-derived free radicals in postischemic tissue injury. N Engl J Med 312:159-163, 1985. 47. Granger DN: Role of xanthine oxidase and granulocytes in ischemia-reperfusion injury. Am J Physiol 255:H1269-H1275, 1988.

Weinberg 48. Weinberg JM: The cell biology of ischemic renal injury. Kidney In1 39:476-500, 1991. 49. Weinberg JM: Oxygen deprivation-induced injury to isolated rabbit kidney tubules. J Clin Invesr 76:1193-1208, 1985. 50. Weinberg JM, Davis JA, Abanua M, Rajan T: Cytoprotective effects of glycine and glutathione against hypoxic injury to renal tubules. J Clin Invesr 80:1446-1454, 1987. 51. Weinberg JM, Davis JA, Abarzua M, Kiani T: Relationship between cell ATP and glutathione content and protection by glycine against hypoxic proximal tubule cell injury. J Lab Clin Med 113:612-623, 1989. 52. Weinberg JM, Davis JA, Abarzua M, Kiani T: Glycine-dependent protection of proximal tubules against lethal cell injury due to inhibitors of mitochondrial ATP production. Am J Physiol 258: C1127-Cl140, 1990. 53. Gronow G, Klause N, Malyusz M: Support of hypoxic renal cell volume regulation by glycine. Adv Erp Med Biol277:705-712, 1990. 54. Mandel LJ,Schnellmann RG, Jacobs WR: Intracellular glutathione in the protection from anoxic injury in renal proximal tubules. J Clin Invesr 85:3 16-324, 1990. 55. Baines AD, Shaikh N, Ho P: Mechanisms of perfused kidney cytoprotection by alanine and glycine. Am J Physiol259:F80-F87, 1990. 56. Silva P, Rosen S, Spokes K, Epstein FH: Effect of glycine on medullary thick ascending limb injury in perfused kidneys. Kidney Int 39:653-658, 1991. 57. Weinberg JM, Venkatachalam MA, Roeser NF,Davis JA, Varani J, Johnson KJ: Amino acid protection of cultured kidney tubule cells against calcium iomphore-induced lethal cell injury. Lab Invest 65:671-678, 1991. 58. Mash DC, Hjelmhaug JA, Vreugdenhil PK, Belzer FO, Southard JH: Glycine prevention of cold ischemic injury in isolated hepatocytes. Cryobiology 28:105-109, 1991. 59. Dickson RC, Bronk SF, Gores GJ: Mechanism of protection by glycine against lethal hepatocellular injury during ATP depletion. Clin Res 39:236A, 1991 (abstract). 60. Weinberg JM, Varani J, Johnson KI, Roeser NF, Dame MK,Davis JA, Venkatachalam MA: Protection of human umbilical vein endothelial cells by glycine and structurally similar amino acids against calcium and hydrogen peroxide-induced lethal cell injury. Am J Parhol 140:457-471, 1992. 61. Garza-Quintero R, Ortega-Lopez J, Stein JH, Venkatachalam MA: Alanine protects rabbit proximal tubules against anoxic injury in vifro. Am J Physiol258:F1075-F1083, 1990. 62. Weinberg JM, Venkatchalam MA, Gana-Quintero R, Roeser NF, Davis JA: Structual requirements for protection by small amino acids against hypoxic injury in kidney proximal tubules. FASEB J 4:3347-3354, 1990. 63. Epstein FH, Heyman SN, Spokes K, Rosen S: Mechanism of glycine protection in hypoxic injury: Analogies with glycine recep tor. J Am Soc Nephrol 1595, 1990 (abstract). 64. Weinberg JM, Davis JA, Roeser NF,Venkatachalam MA: Role of increased cytosolic free calcium in the pathogenesis of rabbit proximal tubule cell injury and protection by glycine or acidosis. J Clin Invest 87581-590, 1991. 65. Weinberg JM, Buchanan DN, Davis JA, Abanua M: Metabolic aspects of protection by glycine against hypoxic injury to isolated proximal tubules. J Am SOCNephrol 1:949-958, 1991.

Ren Fail Downloaded from informahealthcare.com by Monash University on 11/13/14 For personal use only.

Glutathione and Glycine in ARF

66. Weinberg JM, Davis JA, Abarzua M, Smith RK, Kunkel R: Ouabain-induced lethal proximal tubule cell injury is prevented by glycine. Am J Physiol258:F346-F355, 1990. 67. Davis JA, Weinberg JM: Effects of glycine and GSH on toxic maneuvers altering tubule cell plasma membrane cation permeability. Clin Res 36:517A, 1988 (abstract). 68. Weinberg JM, Davis JA: A comparison between protection by glycine, acidosis, and mannitol against proximal tubule cell injury. Clin Res 38:577A, 1990 (abstract). 69. Weinberg JM, Nissim Ilana, Roeser NF, Davis JA, Schultz S , Nissim I: Relationships between imracellular amino acid levels and protection against injury to isolated proximal tubules. Am J Physiol260:410-419, 1991. 70. Barfuss DW, Schafer JA: Active amino acid absorption by proximal convolutedand proximal straight tubules. Am J Physiol236: F149-Fl62, 1979. 71. Barfuss DW, Mays JM, Schafer JA: Pentubular uptake and transepithelial transpon of glycine in isolated proximal tubules. Am J Physiol 238:F324F333, 1980. 72. Duran M-A, Spencer D, Weise M, Kronfol NO, Spencer RF, Oken DE: Renal epithelial amino acid concentratiom in mercury-induced and postischemic acute renal failure. Toxicol Appl Pharmucol 105:183-194, 1990. 73. Venkatachalam MA, Pael YJ, Kreisberg JI, Weinberg JM: Energy thresholds that determine membrane integrity and injury in a renal epithelial cell line (LLC-PKI). Relationships to phospholipid degradation ard unesterified fatty acid accumulation. J Clin Invest 81:745-758, 1988. 74. Glaumann B, Glaumann H, Berezesky IK, Trump BF: Studies on cellular recovery from injury: 11. Ultrastructural studies of the recovery of the pars convoluta of the rat kidney from temporary ischemia. Virchows Arch 24:l-18, 1977. 75. Glaumann G, Glaumann H, Trump BF: Studies on cellular recovery from injury: In. Ultrastructural studies of the recovery of the

319

76. 77. 78.

79.

80.

81.

82.

83.

84.

85.

86.

pars recta of the proximal tubule (P3)segment of the rat kidney from temporary ischemia. Virchows Arch 25:281-308, 1977. Zager RA, Venkatachalam MA: Potentiation of ischemic renal injury by amino acid infusion. Kidney Inr 24:620-625, 1983. Zager RA, Johannes G, Tuttle SE, Sharma HM: Acute amino acid nephrotoxicity. J Lab Clin Med 101:130-140, 1983. McCoy RN, Hill KE, Ayon MA, Stein JH, Burk RF: Oxidant stress following renal ischemia: Changes in the glutathione redox ratio. Kidney Int 33:812-817. 1988. Slusser SO, Grotyohann LW, Martin LF, Scaduto RC: Glutathione catabolism by the ischemic rat kidney. Am J Physiol 258: F1547-Fl553, 1990. Linas SL, Whittenberg D, Repine J: 0,metabolites cause reperfusion injury after short but not prolonged renal ischemia. Am J Physiol253:F685-F691, 1987. Linas SL, Shanley PF, White CW, Parker NP, Repine JE: 0, metabolite-mediated injury in perfused kidneys is reflected by consumption of DMTU and glutathione. Am J Physiol253:F692-F701, 1987. Paller MS: Renal work, glutathione and susceptibility to free radical-mediated postischemic injury. Kidney Inr 33:843-849, 1988. Paller MS, Hebbel RP: Ethane production as a measure of lipid peroxidation after renal ischemia. Am J Physiol25 1:F839-F843, 1986. Scaduto RC Jr, Gattone VH 11, Grotyohann LW, Wertz J, Martin LF: Effect of an altered glutathione content on renal ischemic injury. Am J Physiol255:F911-F921, 1988. Yang HC, Gattone VH, Martin LF, Grotyohann LW, McElroy J, Scaduto RC Jr: The effect of glutathione amtent on renal function following warm ischemia. J Surg Res 46:633-636, 1989. Nath KA, Paller MS, Croatt AJ:Dietary deficiency of antioxidants exacerbates ischemic injury in the rat kidney. Kidney Inr 38: 1109-1 117, 1990.