engleski

Bioavailability of selenosugars in rat

Methyl-2-acetamido-2-deoxy-1-seleno-β -D-galactopyranoside (selenosugar 1) was recently identified as the major urinary selenium metabolite. To obtain information on biological availability and metabolism of selenosugar 1 in relation to biologically available selenite male Wistar strain rats at 8 weeks of age were exposed during 48h to sodium selenite, trimethylselenonium iodide (TMSe), selenosugar 1 or methyl-2-acetamido-2-deoxy-1-seleno-β -D-glucopyranoside (selenosugar 2) in drinking water. Selenium speciation analysis by HPLC/ICPMS was performed on urine samples collected during the exposure. Total selenium in liver, kidney, small intestine and blood was analysed at the end of the experiment by ICPMS following microwave-assisted acid digestion. The major species found in background urine of rats not supplemented with selenium were selenosugar 1 (major metabolite) and TMSe (minor metabolite). The majority of selenium excreted in the urine after ingestion of selenosugars was excreted unchanged, while one part was metabolised, resulting in selenosugar 1 and TMSe as urinary metabolites. As previously reported, ingested TMSe was excreted rapidly and unchanged. Selenium after ingestion of selenite was excreted as selenosugar 1 and TMSe and excretion was slower when compared to selenosugars or TMSe. Ingestion of selenite resulted in increased selenium in the blood and organs, whereas no significant increases in selenium concentration were observed after ingestion of selenosugars or TMSe. The work indicates that selenosugar 1 and selenosugar 2 are at least partly biologically available to rats and undergo metabolism resulting with selenosugar 1 and TMSe as the end products excreted in the urine.

Methyl-2-acetamido-2-deoxy-1-seleno-β -D-galactopyranoside; trimethylselenonium iodide; methyl-2-acetamido-2-deoxy-1-seleno-β -D-glucopyranoside; urine; rat

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