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| Hauptseite > Publikationsdatenbank > Product Study of the Reaction of OH Radicals with Isoprene in the Atmosphere Simulation Chamber SAPHIR |
| Hauptseite > Publikationsdatenbank > Product Study of the Reaction of OH Radicals with Isoprene in the Atmosphere Simulation Chamber SAPHIR |
| Journal Article | PreJuSER-49899 |
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2006
Springer Science + Business Media B.V
Dordrecht [u.a.]
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Please use a persistent id in citations: doi:10.1007/s10874-006-9034-x
Abstract: A previous study compared the effects of folate on methyl metabolism in colon and liver of rats fed a selenium-deficient diet (< 3 microg Se/kg) to those of rats fed a diet containing supranutritional Se (2 mg selenite/kg). The purpose of this study was to investigate the effects of folate and adequate Se (0.2 mg/kg) on methyl metabolism in colon and liver. Weanling, Fischer-344 rats (n = 8/diet) were fed diets containing 0 or 0.2 mg selenium (as selenite)/kg and 0 or 2 mg folic acid/kg in a 2 x 2 design. After 70 d, plasma homocysteine was increased (p < 0.0001) by folate deficiency; this increase was markedly attenuated (p < 0.0001) in rats fed the selenium-deficient diet compared to those fed 0.2 mg Se/kg. The activity of hepatic glycine N-methyltransferase (GNMT), an enzyme involved in the regulation of tissue S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), was increased by folate deficiency (p < 0.006) and decreased by selenium deprivation (p < 0.0003). Colon and liver SAH were highest (p < 0.006) in rats fed deficient folate and adequate selenium. Although folate deficiency decreased liver SAM (p < 0.001), it had no effect on colon SAM. Global DNA methylation was decreased (p<0.04) by selenium deficiency in colon but not liver; folate had no effect. Selenium deficiency did not affect DNA methyltransferase (Dnmt) activity in liver but tended to decrease (p < 0.06) the activity of the enzyme in the colon. Dietary folate did not affect liver or colon Dnmt. These results in rats fed adequate selenium are similar to previous results found in rats fed supranutritional selenium. This suggests that selenium deficiency appears to be a more important modifier of methyl metabolism than either adequate or supplemental selenium.
Keyword(s): Animals (MeSH) ; Colon: cytology (MeSH) ; Colon: drug effects (MeSH) ; Colon: metabolism (MeSH) ; DNA (Cytosine-5-)-Methyltransferase: metabolism (MeSH) ; DNA Methylation: drug effects (MeSH) ; Deficiency Diseases: metabolism (MeSH) ; Deficiency Diseases: pathology (MeSH) ; Folic Acid: administration & dosage (MeSH) ; Folic Acid: metabolism (MeSH) ; Folic Acid: pharmacology (MeSH) ; Glutathione: blood (MeSH) ; Glutathione: metabolism (MeSH) ; Glutathione Peroxidase: metabolism (MeSH) ; Glycine N-Methyltransferase: metabolism (MeSH) ; Homocysteine: blood (MeSH) ; Homocysteine: metabolism (MeSH) ; Liver: cytology (MeSH) ; Liver: drug effects (MeSH) ; Liver: metabolism (MeSH) ; Male (MeSH) ; Rats (MeSH) ; Rats, Inbred F344 (MeSH) ; S-Adenosylhomocysteine: metabolism (MeSH) ; S-Adenosylmethionine: metabolism (MeSH) ; Selenium: administration & dosage (MeSH) ; Selenium: metabolism (MeSH) ; Selenium: pharmacology (MeSH) ; S-Adenosylmethionine ; Homocysteine ; Folic Acid ; Glutathione ; Selenium ; S-Adenosylhomocysteine ; Glutathione Peroxidase ; Glycine N-Methyltransferase ; Gnmt protein, rat ; DNA (Cytosine-5-)-Methyltransferase ; J ; atmosphere simulation chamber (auto) ; isoprene oxidation (auto) ; methacrolein (auto) ; methyl vinyl ketone (auto) ; OH radicals (auto) ; tropospheric ozone (auto)
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