title: 3-OMD and homocysteine plasma levels in parkinsonian patients.
abstract: One main metabolizing pathway of levodopa is O-methylation to 3-O-methyldopa (3-OMD) by catechol-O-methyltransferase (COMT). Since COMT requires Mg2+ and S-adenosylmethionine as methyl donor for this transmethylating process, COMT converts S-adenosylmethionine to S-adenosylhomocysteine and subsequent homocysteine. Objective of this study was to demonstrate relations between plasma levodopa, 3-OMD and total homocysteine in treated parkinsonian subjects. We measured homocysteine, levodopa and 3-OMD by HPLC. We compared plasma homocysteine in two groups of treated parkinsonian subjects subdivided according to their 3-OMD level. Homocysteine was significantly (p = 0.002) elevated in the group with higher 3-OMD concentrations and positively (r = 0.52, p = 0.0006) correlated to 3-OMD. Homocysteine induces vascular disease. Previous studies showed an increase of ischaemic heart- and cerebrovascular disease in treated parkinsonian patients.
authors.affiliation: Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Federal Republic of Germany. thomas.mueller@ruhr-uni-bochum.de
authors.forename: Th
authors.initials: T
authors.lastname: Müller
authors.forename: D
authors.initials: D
authors.lastname: Woitalla
authors.forename: B
authors.initials: B
authors.lastname: Fowler
authors.forename: W
authors.initials: W
authors.lastname: Kuhn
mesh_terms: D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000097:blood*; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007980:Levodopa / Q000097:blood; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood*; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D006710:Homocysteine; D014443:Tyrosine; D007980:Levodopa; D004295:Dihydroxyphenylalanine; C008404:3-methoxytyrosine