In vivo oxidation of the methyl group of hepatic 5-methyltetrahydrofolate.
Methionine given parenterally to rats caused rapid disappearance of methyltetrahydrofolate from the liver and a corresponding rise in tetrahydrofolate and formyl-tetrahydrofolate concentrations. When [14C]H3--H4folate was given, methionine caused an increased [14C]0(2) excretion, indicating that oxidation of the methyl group had occurred. Methionine was more effective than S-adenosylmethionine at causing oxidation, but serine was ineffective. The lowest dose of methionine to produce an effect was 0.5 mumol, which is less than the daily dietary intake in a rat. The data suggest that the concentration of methylfolate in rat livers is controlled by the concentrations of methionine.
Lumb
M
M
Haematology Section, Northwick Park Hospital, Harrow, Middlesex.
Chanarin
I
I
Deacon
R
R
Perry
J
J
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001622:Betaine / Q000494:pharmacology; D002245:Carbon Dioxide / Q000378:metabolism; D003839:Deoxyadenosines; D005575:Formyltetrahydrofolates / Q000378:metabolism; D005998:Glycine / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats; D011919:Rats, Inbred Strains; D012436:S-Adenosylmethionine / Q000494:pharmacology; D012694:Serine / Q000494:pharmacology; D013763:Tetrahydrofolates / Q000378:metabolism*; D013872:Thionucleosides / Q000494:pharmacology; D013997:Time Factors
D003839:Deoxyadenosines; D005575:Formyltetrahydrofolates; D013763:Tetrahydrofolates; D013872:Thionucleosides; D002245:Carbon Dioxide; D001622:Betaine; D012694:Serine; C008500:5'-methylthioadenosine; D012436:S-Adenosylmethionine; D008715:Methionine; D000241:Adenosine; D005998:Glycine; C005984:5-methyltetrahydrofolate