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Title: Clearance of absorbed selenium by the liver

The liver plays a central role in the metabolism of selenium. It secretes plasma selenoproteins, contains a major fraction of the glutathione peroxidase in the body, and synthesizes excretory metabolites. The role of the liver in processing newly absorbed selenium was studied. Male chow-fed rats were fasted overnight and given 24 ng of selenium as {sup 75}SeO{sub 3}{sup 2{minus}} by stomach tube. Animals were exsanguinated at 15, 30, 45, 60, 90, 120, and 180 min after dosing. Comparison of {sup 75}Se uptake by liver, kidney, heart, muscle, testis, brain, and spleen indicated an earlier uptake by liver than by any other tissue. At 15 min, {sup 75}Se in the portal vein blood was 2.6 times that in the hepatic vein blood. Gel filtration analysis suggested a loose association of {sup 75}Se with protein in plasma at 15 min, but immunoprecipitation indicated it was largely in the form of selenoprotein P after 30 min. End-to-side portacaval shunts (PCS) were constructed in rats and sham-operated animals were used as controls. When {sup 75}SeO{sub 3}{sup 2{minus}} was given to animals with PCS, uptake of {sup 75}Se by liver did not precede uptake by other tissues. Also no gradient was detected across the lungsmore » or kidney. {sup 75}Se content of the kidney was higher in PCS rats than in sham-operated rats. This is consistent with removal of the first-pass effect of the liver facilitating uptake of {sup 75}Se by systemic tissues. These results suggest that the preferential uptake of absorbed selenium by the liver is due both to its position in the portal circulation and to an intrinsic high uptake capacity.« less
Authors:
; ; ;  [1]
  1. (Vanderbilt Univ., Nashville, TN (United States))
Publication Date:
OSTI Identifier:
5265226
Report Number(s):
CONF-9104107--
Journal ID: ISSN 0892-6638; CODEN: FAJOE
Resource Type:
Conference
Resource Relation:
Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States); Journal Volume: 5:4; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; LIVER; BIOLOGICAL FUNCTIONS; SELENIUM; METABOLISM; CLEARANCE; IMMUNOASSAY; METALLOPROTEINS; PEROXIDASES; SELENIUM 75; TISSUE DISTRIBUTION; TRACER TECHNIQUES; UPTAKE; BETA DECAY RADIOISOTOPES; BIOASSAY; BODY; DAYS LIVING RADIOISOTOPES; DIGESTIVE SYSTEM; DISTRIBUTION; ELECTRON CAPTURE RADIOISOTOPES; ELEMENTS; ENZYMES; EVEN-ODD NUCLEI; GLANDS; INTERMEDIATE MASS NUCLEI; ISOTOPE APPLICATIONS; ISOTOPES; NUCLEI; ORGANIC COMPOUNDS; ORGANS; OXIDOREDUCTASES; PROTEINS; RADIOISOTOPES; SELENIUM ISOTOPES; SEMIMETALS 560300* -- Chemicals Metabolism & Toxicology