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Erythrocyte glutathione transferase: a general probe for chemical contaminations in mammals

View Article: PubMed Central - PubMed

ABSTRACT

Glutathione transferases (GSTs) are enzymes devoted to the protection of cells against many different toxins. In erythrocytes, the isoenzyme (e-GST) mainly present is GSTP1-1, which is overexpressed in humans in case of increased blood toxicity, as it occurs in nephrophatic patients or in healthy subjects living in polluted areas. The present study explores the possibility that e-GST may be used as an innovative and highly sensitive biomarker of blood toxicity also for other mammals. All distinct e-GSTs from humans, Bos taurus (cow), Sus scrofa (pig), Capra hircus (goat), Equus caballus (horse), Equus asinus (donkey) and Ovis aries (sheep), show very similar amino acid sequences, identical kinetics and stability properties. Reference values for e-GST in all these mammals reared in controlled farms span from 3.5±0.2 U/gHb in the pig to 17.0±0.9 U/gHb in goat; such activity levels can easily be determined with high precision using only a few microliters of whole blood and a simple spectrophotometric assay. Possibly disturbing factors have been examined to avoid artifact determinations. This study provides the basis for future screening studies to verify if animals have been exposed to toxicologic insults. Preliminary data on cows reared in polluted areas show increased expression of e-GST, which parallels the results found for humans.

No MeSH data available.


Changes of GSH, GSSG and e-GST during incubation of bovine blood with peroxide. Bovine blood (1 ml) was incubated with 1.5 mM t-BOOH, and at various times, GSH, GSSG and e-GST were measured. Experimental points are the mean of three different determinations. Error bars are the S.E.M.
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fig3: Changes of GSH, GSSG and e-GST during incubation of bovine blood with peroxide. Bovine blood (1 ml) was incubated with 1.5 mM t-BOOH, and at various times, GSH, GSSG and e-GST were measured. Experimental points are the mean of three different determinations. Error bars are the S.E.M.

Mentions: The absence of oxidized e-GST in normal bovine blood samples does not exclude its presence after severe oxidative stress. Thus, the levels of GSH, GSSG and GSP1-1 were determined after incubation of intact erythrocytes with t-BOOH, a well-known trigger of oxidative stress. Although GSH is rapidly oxidized to GSSG, the activity of e-GST remained unchanged, indicating a strong resistance to oxidants (Figure 3). In addition, the enzymatic cell protection system (glutathione reductase) is rapidly involved and causes a restoration of the original concentration of GSH in <2 h.


Erythrocyte glutathione transferase: a general probe for chemical contaminations in mammals
Changes of GSH, GSSG and e-GST during incubation of bovine blood with peroxide. Bovine blood (1 ml) was incubated with 1.5 mM t-BOOH, and at various times, GSH, GSSG and e-GST were measured. Experimental points are the mean of three different determinations. Error bars are the S.E.M.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4979413&req=5

fig3: Changes of GSH, GSSG and e-GST during incubation of bovine blood with peroxide. Bovine blood (1 ml) was incubated with 1.5 mM t-BOOH, and at various times, GSH, GSSG and e-GST were measured. Experimental points are the mean of three different determinations. Error bars are the S.E.M.
Mentions: The absence of oxidized e-GST in normal bovine blood samples does not exclude its presence after severe oxidative stress. Thus, the levels of GSH, GSSG and GSP1-1 were determined after incubation of intact erythrocytes with t-BOOH, a well-known trigger of oxidative stress. Although GSH is rapidly oxidized to GSSG, the activity of e-GST remained unchanged, indicating a strong resistance to oxidants (Figure 3). In addition, the enzymatic cell protection system (glutathione reductase) is rapidly involved and causes a restoration of the original concentration of GSH in <2 h.

View Article: PubMed Central - PubMed

ABSTRACT

Glutathione transferases (GSTs) are enzymes devoted to the protection of cells against many different toxins. In erythrocytes, the isoenzyme (e-GST) mainly present is GSTP1-1, which is overexpressed in humans in case of increased blood toxicity, as it occurs in nephrophatic patients or in healthy subjects living in polluted areas. The present study explores the possibility that e-GST may be used as an innovative and highly sensitive biomarker of blood toxicity also for other mammals. All distinct e-GSTs from humans, Bos taurus (cow), Sus scrofa (pig), Capra hircus (goat), Equus caballus (horse), Equus asinus (donkey) and Ovis aries (sheep), show very similar amino acid sequences, identical kinetics and stability properties. Reference values for e-GST in all these mammals reared in controlled farms span from 3.5&plusmn;0.2&thinsp;U/gHb in the pig to 17.0&plusmn;0.9&thinsp;U/gHb in goat; such activity levels can easily be determined with high precision using only a few microliters of whole blood and a simple spectrophotometric assay. Possibly disturbing factors have been examined to avoid artifact determinations. This study provides the basis for future screening studies to verify if animals have been exposed to toxicologic insults. Preliminary data on cows reared in polluted areas show increased expression of e-GST, which parallels the results found for humans.

No MeSH data available.