Selenium utilization in humans--a long-term, self-labeling experiment with stable isotopes.
A stable (nonradioactive) isotope of selenium in a chemical form common in foods (selenomethionine) or inorganic selenite was taken orally (200 micrograms/d) for 3 wk to label deep body pools. By deep body pools we mean selenium compartments that are large and/or have a slow turnover (exchange) rate. Blood plasma was removed, stored for 11 mo, and later reinfused as a labeled tracer dose with the selenium label in all of the biologically significant chemical forms. Accessible tissues such as red blood cells were highly labeled (20-25%) in the subjects receiving selenomethionine. Selenium from deep body pools is excreted primarily via the urine (80%). Reexcretion of previously absorbed selenium back into the gastrointestinal tract can be measured, avoiding a major source of error in conventional balance studies used to estimate nutrient absorption.
Veillon
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Beltsville Human Nutrition Research Center, US Department of Agriculture, MD 20705.
Patterson
K Y
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Button
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Sytkowski
A J
AJ
D000284:Administration, Oral; D000328:Adult; D004912:Erythrocytes / Q000032:analysis; D005243:Feces / Q000032:analysis; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007553:Isotope Labeling / Q000379:methods; D007554:Isotopes; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D012643:Selenium / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*; D012645:Selenomethionine / Q000008:administration & dosage / Q000032:analysis / Q000378:metabolism*
D007554:Isotopes; D012645:Selenomethionine; D012643:Selenium