title: Experimental selenium restriction in healthy adult humans: changes in selenium metabolism studied with stable-isotope methodology.
abstract: Mechanisms responsible for selenium homeostasis were investigated in healthy adult men receiving diets adequate or low in Se (eight subjects per group). The appearance of a stable isotope of Se, 74Se, in plasma, urine, and feces was measured after oral administration of 74Se-selenite. One group received a restricted level of Se (18 +/- 1 micrograms/d) for 30 d, which resulted in a decrease in urinary, fecal, and plasma Se content compared with the group that consumed 119 +/- 1 micrograms/d. Low Se intake also resulted in decreased urinary 74Se excretion (27.2 +/- 1.4% vs 32.5 +/- 2.3% of the absorbed dose for the adequate intake), increased body retention of 74Se (74.8 +/- 3.1% vs 67.6 +/- 3.8% of the absorbed dose for the adequate group), and a contracted selenite-exchangeable metabolic pool (Se-EMP) (9782 micrograms for adequate Se and 6314 micrograms for the low-Se group; p less than or equal to 0.05). Measurement of Se-EMP may provide an additional and sensitive approach for assessing Se nutriture in human subjects.
authors.affiliation: Department of Applied Biological Sciences, Massachusetts Institute of Technology, Cambridge.
authors.forename: R F
authors.initials: RF
authors.lastname: Martin
authors.forename: M
authors.initials: M
authors.lastname: Janghorbani
authors.forename: V R
authors.initials: VR
authors.lastname: Young
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D005243:Feces / Q000032:analysis; D006801:Humans; D007554:Isotopes; D008297:Male; D012643:Selenium / Q000032:analysis / Q000172:deficiency / Q000378:metabolism*
chemical_list: D007554:Isotopes; D012643:Selenium