Involvement of tissue sulfhydryls in the formation of a complex of methylmercury with selenium

Metabolic Interactions of Selenium with Cadmium, Mercury, and Silver

“…Work by Yoshida et al (1983) supports the con- cept of selenide as the active species against heavy metals, Selenite and selenocystine were much more effective than selenomethionine in counteracting the depressive effect of silver on GSH-Px activity in rats, It is well known that selenite and selenocystine can be converted to selenide much more readily than can selenomethionine (Sunde and Hoekstra, 1980;Whanger et al, 1980). Work on the formation of bis(methylmercuric)selenide is also consistent with the view that selenide is the critical form of selenium (Iwata et al, 1981). Selenide was more effective in the formation of this complex than selenite, selenate, selenocystine, seleno methionine, or selenotrisulfide.…”

“…Finally, the involvement of tissue .sulfhydryls in the formation of bis(methylmercuric)selenide is another possible mechanism of heavy metal detoxification by selenium Naganuma et al .• 1980). Selenide has been found to react with methylmercury in vitro to form bis(methylmercuric)selenide (reaction 10), but either protein sulfhydryl groups or reduced glutathione was needed when other chemical forms of selenium were used (Iwata et al .• 1981). The detection of selenide, although at very low levels, in the tissues of mice treated with selenium and methylmercury (Naganuma et al .• 1980) is evidence that this reaction occurs in animals.…”

Cadmium-Induced Renal Lipid Peroxidation in Rats and Protection by Selenium

“…Rana and Verma (1996) also reported that Cd failed to induce lipid peroxidation in the liver and kidney in presence of Se. It has been suggested that interaction between Se and Cd is mediated by endogenous glutathione, which reduces selenite to selenide compound (Iwata et al, 1981). The high lipoaffinity of this compound might alter (reduce) its distribution and thus toxicity in critical tissues (Masukawa et al, 1982).…”

The effect of selenium on mercury assimilation by freshwater organisms

“…A literature review by Cuvin-Aralar and Furness (1991) presented several possible mechanisms of protection, including a redistribution or excretion of Hg in the presence of Se, a competition for binding sites between both elements, the formation of Hg-Se complexes, the conversion of toxic forms to less toxic forms of Hg, and the prevention of oxidative damage from Hg by Se through an increased activity of glutathione peroxidase. Among those mechanisms, the formation of an inorganic and (or) protein Hg-Se complex is proposed and frequently supported by analytical evidences derived by traditional chromatographic techniques (Burk et al 1974;Iwata et al 1981;Ping et al 1986), high-performance liquid chromatography (HPLC) combined with inductively coupled plasma-mass spectrometry (ICP-MS; Suzuki 1997a, 1997b;Sasakura and Suzuki 1998), microscopy (Christensen et al 1989), or X-ray techniques (Carmichael and Fowler 1980;Lindh and Johansson 1987;Gailer et al 2000). These complexes are generally found in storage organs such as liver and kidney and even in hair for humans (Soares de Campos et al 2002).…”