title: Levodopa, placebo and rotigotine change biomarker levels for oxidative stress.
abstract: BACKGROUND
  Homocysteine increase and glutathione derivative cysteinyl-glycine fall are indirect biomarkers for oxidative stress, for instance due to dopamine D1receptor stimulation.
  
  
  OBJECTIVE
  To investigate the influence of the D1receptor agonists levodopa and rotigotine compared with placebo on homocysteine and cysteinyl-glycine in plasma of patients with Parkinson's disease.
  
  
  METHODS
  Patients received 100 mg levodopa, 4 mg rotigotine or placebo. Cysteinyl-glycine and homocysteine were measured every 30 min over three hours.
  
  
  RESULTS
  Homocysteine rose during levodopa- and placebo administration. Rotigotine had no effect. Cysteine-glycine only increased after placebo- but not after levodopa- or rotigotine.
  
  
  CONCLUSIONS
  Homocysteine elevation results from hepatic and gastrointestinal methylation processes. Transdermal rotigotine circumvents these methylation locations. Turnover of segregated alkyl residuals from rotigotine serves as methyl group donors, which counteract homocysteine increment. The placebo-related cysteinyl-glycine increase results from reduced free radical exposure. Low levodopa dosing and antioxidants in the rotigotine patch matrix prevented cysteinyl-glycine fall.
authors.affiliation: a Department of Neurology , St. Josef Hospital, Ruhr University Bochum , Bochum , Germany.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Muhlack
authors.affiliation: a Department of Neurology , St. Josef Hospital, Ruhr University Bochum , Bochum , Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Kinkel
authors.affiliation: a Department of Neurology , St. Josef Hospital, Ruhr University Bochum , Bochum , Germany.
authors.forename: Lennard
authors.initials: L
authors.lastname: Herrman
authors.affiliation: b Department of Neurology , St. Joseph Hospital Berlin-Weissensee , Berlin , Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Müller
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D002851:Chromatography, High Pressure Liquid; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives / Q000097:blood; D004151:Dipeptides / Q000097:blood*; D015259:Dopamine Agents / Q000008:administration & dosage* / Q000097:blood; D055664:Electrochemical Techniques; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage* / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects; D010300:Parkinson Disease / Q000097:blood / Q000188:drug therapy; D013764:Tetrahydronaphthalenes / Q000008:administration & dosage* / Q000097:blood; D013876:Thiophenes / Q000008:administration & dosage* / Q000097:blood; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives
chemical_list: D004151:Dipeptides; D015259:Dopamine Agents; D013764:Tetrahydronaphthalenes; D013876:Thiophenes; D006710:Homocysteine; C028505:cysteinylglycine; D014443:Tyrosine; D007980:Levodopa; D004295:Dihydroxyphenylalanine; C047508:rotigotine; C008404:3-methoxytyrosine
keywords: Homocysteine; Parkinson’s disease; cysteinyl-glycine; levodopa; oxidative stress; placebo; rotigotine