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A human model of selenium that integrates metabolism from selenite and selenomethionine 1-3

Permanent URL:
http://handle.nal.usda.gov/10113/58139
Abstract:
Selenium (Se) metabolism is determined by the various chemical forms of the element in foods and diets, by the incorporation of the element both specifically and non-specifically into multiple proteins, and by gender. Modeling may help clarify these issues. While the kinetics of Se forms have been compared in different subjects, or the same subjects at different times, direct comparisons of their respective metabolism have not been made. The aim of this study was to compare the kinetics of absorbed Se from inorganic selenite (Sel) and selenomethionine (SeMet) simultaneously in healthy subjects (n=31). After PO administration of stable isotopic tracers of each form, urine and feces were collected for 12 d and blood was sampled over 4 mo. Tracer enrichment was determined by isotope-dilution-gas chromatography/mass spectrometry. Using WinSAAM, a compartmental model was fitted to the data. Within 30 min of ingestion, Se from both forms entered a common pool, and metabolism was similar for several days before diverging. Slowly turning-over pools were required in tissues and plasma for Se derived from SeMet to account for its three-fold higher incorporation into RBC compared to Se from Sel; these presumably represent non-specific incorporation of SeMet into proteins. Pool sizes and transport rates were determined and compared by form and gender. The final model consisted of eleven plasma pools, two pools and a delay in RBC, and extravascular pools for recycling of Se back into plasma. This model will be used to evaluate changes in Se metabolism following long-term (2 y) Se supplementation.
Author(s):
Meryl E. Wastney , Gerald F. Combs , Wesley K. Jr. , Philip R. Canfield , Kristine Y. Taylor , A. David Patterson , James E. Hill , Blossom H. Moler
Subject(s):
absorption , animal tissues , blood plasma , dietary supplements , erythrocytes , feces , foods , gas chromatography , gender , humans , ingestion , isotope dilution technique , kinetics , mass spectrometry , models , protein synthesis , proteins , recycling , selenites , selenium , selenomethionine , stable isotopes , tracer techniques , urine
Source:
Journal of nutrition 2011 4 1 v.141
Language:
English
Year:
2011
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.