Polymorphism of Glutathione S-Transferase (GST) Variants and Its Effect on Distribution of Urinary Arsenic Species in People Exposed to Low Inorganic Arsenic in Tap Water: An Exploratory Study

ABSTRACT

Glutathione S-tranferases (GST) are multigenic enzymes that have been associated with arsenic metabolism. The objective of this study was to evaluate the relationship between polymorphic variants of GST and urinary concentration of arsenic species in people exposed to low levels of arsenic. A cross-sectional study among 66 nonoccupationally exposed subjects, living in the city of Antofagasta, Chile. Polymorphic variants were analyzed by polymerase chain reaction (PCR) and arsenic species was determined by atomic absorption spectrometry. The effect of GST variants on arsenic concentration was evaluated using univariate and covariate-adjusted regressions. For both GSTT1 and GSTM1 there were no significant differences in detected arsenic relative species between carriers of the active and null polymorphic variants. There was nondefinitive evidence that polymorphic variants of GST play a role in arsenic metabolism in sample of the Chilean subjects studied.

KEYWORDS:

• arsenic
• exposure assessment
• genetic polymorphism
• risk assessment

Acknowledgments

Financial support was provided by FOGARTY N° D43TW05746. International Training and Research In Environmental and Occupational Health (ITREOH). National Institute of Health, USA, and REIN N° 05/02 project of the Department of Investigation (DI) of the University of Chile.

The authors want to express their gratitude to Dr Kyle Steenland of Emory University, USA, for his comments, and to Dr David L. Rosen of the University of North Carolina at Chapel Hill, USA, for his review of the manuscript.

Notes

*Mean, standard deviation.

**mean, range.

*Creatinine-adjusted.

*Creatinine-adjusted.

*Covariates included total inorganic arsenic, age, sex, BMI, number of cigarettes the previous day, consumption of tap water, beverage and seafood. R ²* adjusted. I-As = inorganic arsenic; MMA = monomethylarsonic acid; DMA: dimethylarsinic acid.