Vanadate and selenium inhibit the triiodothyronine induced enzyme activity and mRNA level for both fatty acid synthase and malic enzyme

Conference · Fri Mar 15 04:00:00 EST 1991 · FASEB Journal (Federation of American Societies for Experimental Biology); (United States)

OSTI ID:5145496

Zhu, Y; Mirmiran, R; Goodridge, A G; Stapleton, S R ^[1]

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1. Univ. of Iowa, Iowa City (United States) Western Michigan Univ., Kalamazoo (United States)

In chick-embryo hepatocytes in culture, triiodothyronine stimulates enzyme activity, mRNA level and transcription rate for both fatty acid synthase (FAS) and malic enzyme (ME). Insulin alone has no effect but amplifies the induction by T3. Recent evidence has demonstrated the insulin-mimicking action of vanadate and selenium on various physiological processes. Little information, however, is available on the affects of vanadate and selenium on the expression of genes that are regulated by insulin. These studies were initiated to test the potential of vanadate and selenium to mimic the amplification affect of insulin on the T3 induction of FAS and ME. In chick-embryo hepatocytes incubated in a chemically defined medium, addition of T3 for 48h causes an increase in the enzyme activity and mRNA level for both FAS and ME. Addition of sodium vanadate or sodium selenate (20 {mu}M) coincident with the T3 almost completely inhibited the stimulation of FAS and ME activity and accumulation of their respective mRNA's. Fifty percent maximal inhibition occurred at about 3-40{mu}M vanadate or 5-10{mu}M selenium. Vanadate and selenium similarity inhibited FAS and ME enzyme activity and mRNA level when the cells were incubated in the presence of insulin and T3. The effect of these metals was selective; isocitrate dehydrogenase activity as well as the level of glyceraldehyde 3-phosphate mRNA were not affected by any of the additions made to the cells in culture. This effect by vanadate and selenium also does not appear to be a generalized effect of metals on lipogenic enzymes as molydate under similar experimental conditions has no effect on either the enzyme activity or mRNA level of FAS or ME. Studies are continuing to determine the mechanism of action of these agents on the regulation of lipogenic enzymes.

• OSTI ID: 5145496
• Report Number(s): CONF-9104107--
• Conference Information: Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Journal Volume: 5:5
• 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.
ANIMAL CELLS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIRDS
CHICKENS
ELEMENTS
EMBRYOS
ENZYME ACTIVITY
ENZYMES
FOWL
HORMONES
INHIBITION
KINETICS
LIGASES
LIVER CELLS
MESSENGER-RNA
METABOLISM
METALS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PROTEINS
REACTION KINETICS
RNA
SELENIUM
SEMIMETALS
SOMATIC CELLS
THYROID HORMONES
TRANSCRIPTION
TRANSITION ELEMENTS
TRIIODOTHYRONINE
VANADIUM
VERTEBRATES