Uptake of ⁵¹Cr‐Chromate by Human Erythrocytes – A Role of Glutathione

Abstract

Hexavalent chromium (Cr‐VI), as Na2CrO4 in an aquous solution, was reduced rapidly to the trivalent form (Cr‐III) in the presence of glutathione, GSH (0.3–3.0 mM). Such GSH‐dependent reduction of Cr‐VI can take place in the cytosolic space of Cr‐VI‐exposed cells, since GSH is found in reactive concentrations in this compartment. The reduction makes chromium essentially impermeable through the cell membrane, explaining the observation that Cr‐VI, when added to red cell suspensions, is bound quantitatively intracellularly after a few hours. Diethylmaleate conjugation of the SH‐group of the intracellular GSH preventing the oxidation to GSSG, lowered the chromium‐uptake significantly, showing that reduced GSH plays a role for the chromium binding. In healthy red cells chromium is partially bound to haemoglobin and partially to small molecular weight substances, probably in the trivalent form. This intracellular chromium cannot be removed to the extracellular space by addition of chelating agents as long as the cell membrane is intact.

Interaction Algae–Bacteria Consortia: A New Application of Heavy Metals Bioremediation

“…According to Shen and Wang ( 1993 ), Cr (III) formed by Escherichia coli ATCC 33456 from the reduction of Cr (VI) probably adheres to the surface of cells, indicating that previous studies showed that when the Cr (VI) is reduced to Cr (III), Cr (III) cannot be removed intracellularly when the cell membrane remains intact. Aaseth et al ( 1982 ), allowed us to reinforce the deduction that the chromium reduction in this case could be presented extracellularly.…”

Xenobiotics, Trace Metals and Genetics in the Pathogenesis of Tauopathies

“…It was found that the soil in these regions was contaminated with hexavalent chromium [33]. It is known that chromate, which rapidly traverses biological membranes [34], exerts toxic effects on mitochondria [35,36]. Another cluster with PSP-resembling symptomatology has been described in a region that was previously active in iron and copper mining in eastern Norway [37].…”

Review article. Adverse hematological effects of hexavalent chromium: an overview

“…As discussed earlier, Cr (VI) taken up by RBCs undergoes reduction to the trivalent form with the help of reduced glutathione (Wiegand et al ., 1984 ) and complexes with Hgb and other intracellular proteins that are sufficiently stable to retain chromium for a substantial fraction of the RBC lifetime (Aaseth et al ., 1982 ). This was confirmed by the result of an experiment where K 2 Cr 2 O 7 , a hexavalent chromium compound, introduced into plasma and reconstituted whole blood from three individuals was found to be readily reduced to Cr (III) in the concentration range of 100–1,000 μg Cr (VI)/L (Corbett et al ., 1998 ).…”

“…This was confirmed by the result of an experiment where K 2 Cr 2 O 7 , a hexavalent chromium compound, introduced into plasma and reconstituted whole blood from three individuals was found to be readily reduced to Cr (III) in the concentration range of 100–1,000 μg Cr (VI)/L (Corbett et al ., 1998 ). Excess trivalent chromium in the RBC is sequestered until cell death (Kerger et al ., 1997; Aaseth et al ., 1982 ). Over time, the RBC-associated chromium appears to be transferred to the spleen as a result of scavenging aging RBCs from the blood.…”