Metabolism of subtoxic level of selenite by double-perfused small intestine in rats.

Intestinal metabolism of the subtoxic level of selenite in rats was investigated using a double-perfusion system, which is an in situ, in vitro preparation in which the intestinal lumen and its vasculature are perfused simultaneously. The toxicity of sodium selenite was determined by inhibition of 3-O-methyl glucose (3MG) absorption and by histological examination. Levels of 1.

Dietary selenium increases selenoprotein W levels in rat tissues.

Two experiments were conducted to evaluate the influence of dietary selenium (Se) on tissue levels of selenoprotein W (Se-W) in rats. Se dependent glutathione peroxidase (GPX) activity and Se levels were also determined for comparative measurements. In the first experiment, rats were fed a basal diet deficient in Se or supplemented with either 0.

Selenoprotein W cDNAs from five species of animals.

The nucleotide sequences of the open reading frames of cDNAs for selenoprotein W from skeletal muscle of rat, mouse, sheep, rhesus monkey and human are reported. Theoretical translation of the coding sequences indicated highly similar proteins of 88 (mouse and rat) or 87 (human, monkey and sheep) amino acids. In 73 of 88 positions the specified amino acids are identical for all five proteins.

Conserved features of selenocysteine insertion sequence (SECIS) elements in selenoprotein W cDNAs from five species.

SECIS elements form stem-loop structures in the 3' untranslated regions (UTR) of eukaryotic mRNAs that encode selenoproteins. These elements direct incorporation of selenocysteine at UGA codons, provided the SECIS element lies a sufficient distance from the UGA. The cDNAs encoding skeletal muscle selenoprotein W from human, rhesus monkey, sheep, rat, and mouse contained highly similar SECIS elements that retained important features common to all known SECIS elements.

Metabolism of subtoxic levels of selenium in animals and humans.

Since high levels of selenium are used as cancer chemopreventive agents in animals and humans, a better understanding of the metabolism of subtoxic levels is desirable. Absorption from rat small intestine using in situ double perfusion, ligated intestinal segments, and brush border membrane vesicles (BBMV) was used to study selenium absorption. A level of 1.