Interaction of Mercury with Human Erythrocytes

Abstract

The binding of mercury to red blood cells was measured in terms of Hg203 uptake and desorption. The significant features of the binding are: (a) rapid achievement of equilibrium (3 to 5 minutes); (b) release of a Hg-complexing material from the red cells themselves which distorts the binding curves at low concentrations of metal (2.5 x 10-7 to 5.0 x 10-6 M); (c) prevention of binding by cysteine, glutathione, penicillamine, and EDTA but not by imidazole or histidine; (d) binding of mercury in amounts up to 7 times the reduced glutathione concentration of the cells before combination with glutathione itself; (e) binding primarily to sulfhydryl groups of hemoglobin and to a small number of stromal sulfhydryl groups, but also to other non-sulfhydryl cellular ligands after saturation of the sulfhydryl groups. Associated with the binding is inhibition of glucose uptake, induction of loss of K+, and decrease in osmotic fragility. These effects increase over the range of concentrations (1 x 10-17 to 1 x 10-15 moles of Hg/RBC) well below those that result in saturation of the cellular binding sites; above 1 x 10-15 moles/RBC, the effects decrease as the cells become saturated.