title: [Selenium methylation and toxicity mechanism of selenocystine].
abstract: Selenium is an essential trace element and a toxicant for animals. Selenocystine, a selenium-containing amino acid, is one of the chemical forms in which selenium exists in food. This review summarized recent studies on the toxicity mechanism of selenocystine in experimental animals. Hepatotoxicity is caused by repeated oral administration of selenocystine. Selenocystine is metabolized by reduced glutathione and/or glutathione reductase to hydrogen selenide via selenocysteine-glutathione selenenyl sulfide. The hydrogen selenide is a key intermediate in the selenium methylation metabolism of inorganic and organic selenium compounds. Accumulation of the hydrogen selenide resulting from inhibition of the selenium methylation metabolism, detoxification metabolic pathway of selenium, is found in animals following repeated administration of a toxic dose of selenocystine. The excess of the hydrogen selenide produced by inhibition of the selenium methylation metabolism contributes to the hepatotoxicity caused by selenocystine.
authors.affiliation: Faculty of Pharmaceutical Sciences, Setsunan University, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sayato
authors.forename: K
authors.initials: K
authors.lastname: Nakamuro
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D056486:Chemical and Drug Induced Liver Injury; D003553:Cystine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D008658:Inactivation, Metabolic; D008099:Liver / Q000378:metabolism; D008716:Methionine Adenosyltransferase / Q000378:metabolism; D008745:Methylation; D016566:Organoselenium Compounds / Q000378:metabolism* / Q000633:toxicity*; D012643:Selenium / Q000378:metabolism; D018036:Selenium Compounds / Q000378:metabolism
chemical_list: D016566:Organoselenium Compounds; D018036:Selenium Compounds; C009226:selenocystine; D003553:Cystine; D005980:Glutathione Reductase; D008716:Methionine Adenosyltransferase; D012643:Selenium; C026372:hydrogen selenide