Effect of dietary selenium on the 5 prime -deiodinase activity of washed microsomes from rat liver

Conference · Mon Mar 11 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5373487

Vadhanavikit, S; Ganther, H E ^[1]

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1. Univ. of Wisconsin, Madison (United States)

Male Sprague Dawley rats were fed a Torula yeast-based diet containing 0.1 ppm Se as selenite (+Se) or the diet without selenium supplementation ({minus}Se). At 6 months, rats were sacrificed and liver microsomes and cytosol were prepared. Glutathione peroxidase activity of (+SE) and ({minus}Se) cytosol was 0.86 {plus minus} 0.07 and 0.02 {plus minus} 0.01 U/mg, respectively. Microsomal 5{prime}-deiodinase, Type I (5{prime}-DI) was assayed in the presence of 3 mM DTT using ({sup 125}I) reverse triiodothyronine (rT{sub 3}) as substrate and the released {sup 125}I{sup {minus}} was determined. 5{prime}-DI activity of (+Se) and ({minus}Se) microsomes was 3.99 {plus minus} 0.29 and 0.43 {plus minus} 0.12 U/mg, respectively. Mixing experiments showed that (a) cytosol from (+Se) animals had very little or no stimulating effect on 5{prime}-DI activity of ({minus}Se) microsomes, and (b) ({minus}Se) cytosol as well as ({minus}Se) microsomes had no inhibitory effect on (+Se) microsomes. It is concluded that 5{prime}-DI activity is greatly decreased in microsomes of Se-deficient rats, and is not restored to normal by the addition of cytosol from Se-adequate animals. These results confirm and extend the authors' previous report of reduced 5{prime}-DI activity in Se-deficient rats when measured as the conversion of thyroxine to T{sub 3} in whole homogenates.

• OSTI ID: 5373487
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:4
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AMINO ACIDS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOASSAY
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DIET
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
ENZYME ACTIVITY
ENZYME IMMUNOASSAY
ENZYMES
GLANDS
HORMONES
IMMUNOASSAY
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIVER
MAMMALS
METABOLISM
MICROSOMES
NUCLEI
NUTRITIONAL DEFICIENCY
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
OXIDOREDUCTASES
PEPTIDE HORMONES
PEROXIDASES
PROTEINS
RADIOISOTOPES
RATS
RIBOSOMES
RODENTS
SELENIUM
SEMIMETALS
THYROID HORMONES
THYROXINE
TRACER TECHNIQUES
TRIIODOTHYRONINE
VERTEBRATES