Arsenate V induced glutathione efflux from human erythrocytes

Developmental and interactive effects of arsenic and chromium to developing Ambystoma maculatum embryos: Toxicity, teratogenicity, and whole-body concentrations

Anthropogenic activity has contributed to elevated environmental concentrations of arsenic (As) and chromium (Cr). The spotted salamander, Ambystoma maculatum, may be useful for identifying developmental effects produced by exposure to these contaminants as adults breed and larvae develop in water that may contain As or Cr. Three sample sets among 700 developing larvae were exposed to a range of As, Cr, or 2.5:1 mixture of As:Cr concentrations, respectively. From these 700 larvae, samples containing approximately 24 larvae showed different patterns of whole-body As and Cr from individual and mixture exposure. Whole-body As concentrations were 20.27 and 45.4 µg/g dry weight for larvae exposed to 20 mg/L As and 25:10 mg/L As:Cr, respectively, while whole-body Cr concentrations were 24.8 and 22 µg/g dry weight for larvae exposed to 20 mg/L Cr and 25:10 As:Cr, respectively. Observed malformations included edema, tail kinking, facial deformities, and abnormal bending. Twelve-day lethal concentrations for As and Cr in Ambystoma maculatum larvae were 261.17 mg/L and 71.93 mg/L, respectively, while 12-d effective concentrations to induce malformations were 158.82 and 26.05 mg/L, giving teratogenic indices of 1.64 and 2.76 for individual metal exposure. Exposure to a mixture of As and Cr resulted in a response addition and yielded lower lethal and effective concentration values with a teratogenic index of 2.78, indicating that these contaminants are developmentally toxic at lower concentrations when exposed as a mixture. Data demonstrate that As and Cr affect development of amphibian larvae, and that Ambystoma maculatum may be a useful indicator of environmental toxicity for these metals.

Toxicity of Glutathione-Binding Metals: A Review of Targets and Mechanisms

Mercury, cadmium, arsenic and lead are among priority metals for toxicological studies due to the frequent human exposure and to the significant burden of disease following acute and chronic intoxication. Among their common characteristics is chemical affinity to proteins and non-protein thiols and their ability to generate cellular oxidative stress by the best-known Fenton mechanism. Their health effects are however diverse: kidney and liver damage, cancer at specific sites, irreversible neurological damages with metal-specific features. Mechanisms for the induction of oxidative stress by interaction with the cell thiolome will be presented, based on literature evidence and of experimental findings.

Arsenate stimulates glutathione export from viable cultured rat cerebellar granule neurons

Arsenate is an environmental pollutant which contaminates the drinking water of millions of people worldwide. Numerous in vitro studies have investigated the toxicity of arsenate for a large number of different cell types. However, despite the known neurotoxic potential of arsenicals, little is known so far about the consequences of an exposure of neurons to arsenate. To investigate acute effects of arsenate on the viability and the glutathione (GSH) metabolism of neurons, we have exposed primary rat cerebellar granule neuron cultures to arsenate. Incubation of neurons for up to 6 h with arsenate in concentrations of up to 10 mM did not acutely compromise the cell viability, although the cells accumulated substantial amounts of arsenate. However, exposure to arsenate caused a time- and concentration-dependent increase in the export of GSH from viable neurons with significant effects observed for arsenate in concentrations above 0.3 mM. The arsenate-induced stimulation of GSH export was abolished upon removal of arsenate and completely prevented by MK571, an inhibitor of the multidrug resistance protein 1. These results demonstrate that arsenate is not acutely toxic to neurons but can affect the neuronal GSH metabolism by stimulating GSH export.