Effect Of Mercury, Selenium And Glutathione On Sulfhydryl Levels And Glutathione-Reductase In Blood Clam <i>Anadara-Granosa</i> (L)

Abstract

Effects of Hg, Se and glutathione (GSH) on sulphydryl levels (SH) and glutathione reductase (GSSG-R) in an arcid blood clam <i>A. granosa</i> were evaluated. Exposure to Hg (0.1 mgl^-1, as HgCl₂) alone and in the presence of Se (1 mgl^-1, as SeO₂) significantly increased SH levels in digestive glands, blood and erythrocytes, but reduced them in gills in relation to control clams. GSH, on the other hand, produced no significant changes in thiol content. Treatment with Hg + GSH conversely restored SH levels to the control range in these tissues. GSSG-R activity in the erythrocytes was significantly reduced on exposure to Hg alone and in the presence of Se. Complete amelioration of the enzyme activity was recorded after treatment with Hg + GSH. The results demonstrate that at least in marine clams, GSH plays an important role in offering protection against toxic effects of inorganic Hg at cellular levels, whereas Se does not.