作者: Dietrich Behne , Antonios Kyriakopoulos , Hildegard Gessner , Barbara Walzog , Harald Meinhold
关键词:
摘要: Type I iodothyronine deiodinase (I-D), which catalyzes the production of thyroid hormone 3,3',5-triiodothyronine from thyroxine, has recently been identified as a selenoenzyme. It is therefore interest to investigate relationships between selenium and iodine metabolism. In livers Se-deficient rats I-D activity was inhibited; 3,3'-diiodothyronine added thyroxine decreased by greater than 95% relative Se-adequate controls. The hepatic also reduced in fed diet with low concentration. Unaltered glutathione peroxidase activities liver plasma these suggest, however, that normal Se intake this metabolic pathway not affected depletion. When were administered 75Se-labeled at levels equal amounts ingested diets concentrations 0.3 or 2 mg Se/kg, found animals receiving higher dosage. thyroidal concentrations, comparable Se/kg selenite L-selenomethionine. measurement showed excessive supply does elevate two enzymes but might even have opposite effect. At high tissue concentration cannot be used indicator selenoenzyme activities.