Influence of vitamin B12 on brain methionine adenosyltransferase activity in senile dementia of the Alzheimer's type.
The influence of vitamin B12 on the activity of methionine adenosyltransferase (MAT) in postmortem brains of patients with senile dementia of the Alzheimer's type (SDAT) was investigated. In samples of cortex gyrus frontalis from SDAT patients with normal and low levels of serum B12, MAT Vmax was significantly increased by 25% and 19%, respectively. MAT Vmax from a SDAT group chronically treated with B12 was similar to controls. In contrast to cortex gyrus frontalis, no significant alterations were seen in MAT activity in nucleus caudatus. This study provides evidence that SDAT is associated with significant alterations in transmethylation mechanisms in specific regions of the brain. The relationship between blood levels of B12 and the actual status of this vitamin in the brain influencing the rates of synthesis of both methionine and SAM may, however, be far more complex and cannot be directly clarified on the basis of the present human brain results.
Gomes-Trolin
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Department of Medical Pharmacology, University of Uppsala, Sweden.
Gottfries
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Regland
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Oreland
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L
D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000188:drug therapy* / Q000201:enzymology; D000704:Analysis of Variance; D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000187:drug effects* / Q000201:enzymology; D005260:Female; D005492:Folic Acid / Q000378:metabolism; D006179:Gyrus Cinguli / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D008297:Male; D008716:Methionine Adenosyltransferase / Q000378:metabolism*; D014805:Vitamin B 12 / Q000097:blood / Q000494:pharmacology*
D005492:Folic Acid; D008716:Methionine Adenosyltransferase; D014805:Vitamin B 12