TY  - JOUR
AU  - Karl, M.
AU  - Dorn, H. P.
AU  - Holland, F.
AU  - Koppmann, R.
AU  - Poppe, D.
AU  - Rupp, L.
AU  - Schaub, A.
AU  - Wahner, A.
TI  - Product Study of the Reaction of OH Radicals with Isoprene in the Atmosphere Simulation Chamber SAPHIR
JO  - Journal of atmospheric chemistry
VL  - 55
SN  - 0167-7764
CY  - Dordrecht [u.a.]
PB  - Springer Science + Business Media B.V
M1  - PreJuSER-49899
SP  - 167 - 187
PY  - 2006
N1  - Record converted from VDB: 12.11.2012
AB  - 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.
KW  - Animals
KW  - Colon: cytology
KW  - Colon: drug effects
KW  - Colon: metabolism
KW  - DNA (Cytosine-5-)-Methyltransferase: metabolism
KW  - DNA Methylation: drug effects
KW  - Deficiency Diseases: metabolism
KW  - Deficiency Diseases: pathology
KW  - Folic Acid: administration & dosage
KW  - Folic Acid: metabolism
KW  - Folic Acid: pharmacology
KW  - Glutathione: blood
KW  - Glutathione: metabolism
KW  - Glutathione Peroxidase: metabolism
KW  - Glycine N-Methyltransferase: metabolism
KW  - Homocysteine: blood
KW  - Homocysteine: metabolism
KW  - Liver: cytology
KW  - Liver: drug effects
KW  - Liver: metabolism
KW  - Male
KW  - Rats
KW  - Rats, Inbred F344
KW  - S-Adenosylhomocysteine: metabolism
KW  - S-Adenosylmethionine: metabolism
KW  - Selenium: administration & dosage
KW  - Selenium: metabolism
KW  - Selenium: pharmacology
KW  - S-Adenosylmethionine (NLM Chemicals)
KW  - Homocysteine (NLM Chemicals)
KW  - Folic Acid (NLM Chemicals)
KW  - Glutathione (NLM Chemicals)
KW  - Selenium (NLM Chemicals)
KW  - S-Adenosylhomocysteine (NLM Chemicals)
KW  - Glutathione Peroxidase (NLM Chemicals)
KW  - Glycine N-Methyltransferase (NLM Chemicals)
KW  - Gnmt protein, rat (NLM Chemicals)
KW  - DNA (Cytosine-5-)-Methyltransferase (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:16632891
UR  - <Go to ISI:>//WOS:000240803000004
DO  - DOI:10.1007/s10874-006-9034-x
UR  - https://juser.fz-juelich.de/record/49899
ER  -