title: Acute tryptophan depletion increases experimental nausea but also induces hunger in healthy female subjects.
abstract: BACKGROUND
  Acute tryptophan depletion (ATD) is an experimental model to reduce central serotonin levels.
  
  
  METHODS
  Thirty-eight healthy female subjects were randomly assigned to two groups (ATD and control) in a randomized, double-blinded parallel-group design. Following a standardized and balanced amino acid diet (including 1.21 g tryptophan) on the first day, they received either a protein drink without tryptophan (but substituted by other amino acids) (ATD condition) or the balanced protein drink with tryptophan (control condition) 24 h later. Four hours after its consumption, they were exposed to a standard rotation procedure. Symptom ratings (SR), ratings of hunger and mood scores were taken prior to rotation, at each break, and 15 and 30 min thereafter, together with saliva cortisol samples.
  
  
  RESULTS
  Five subjects could not tolerate the entire rotation procedure and were excluded from analysis. For the remaining n = 33, SR and hunger ratings were higher during ATD than during control conditions, but mood was unaffected. Cortisol levels rose significantly with rotation but were unaffected by ATD. High baseline cortisol levels were associated with lower SR during rotation. The protective effects of morning cortisol were pronounced during the menstrual and follicular phase of the cycle and not present during ovulation and the luteal phase.
  
  
  CONCLUSIONS
  Acute tryptophan depletion is associated with increased symptoms of nausea in healthy female subjects when exposed to body rotation. Acute tryptophan depletion also increases hunger rating. These opposite effects may indicate independent actions of the serotonin on central and peripheral functions.
authors.affiliation: Department of Internal Medicine VI, University of Tübingen, Tübingen, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Rieber
authors.forename: D
authors.initials: D
authors.lastname: Mischler
authors.forename: V
authors.initials: V
authors.lastname: Schumacher
authors.forename: E
authors.initials: E
authors.lastname: Muth
authors.forename: S
authors.initials: S
authors.lastname: Bischoff
authors.forename: S
authors.initials: S
authors.lastname: Klosterhalfen
authors.forename: S
authors.initials: S
authors.lastname: Zipfel
authors.forename: P
authors.initials: P
authors.lastname: Enck
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000032:analysis; D002648:Child; D004044:Dietary Proteins / Q000032:analysis / Q000494:pharmacology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006815:Hunger / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood; D009325:Nausea / Q000503:physiopathology* / Q000523:psychology; D012399:Rotation; D016037:Single-Blind Method; D014364:Tryptophan / Q000502:physiology*; D055815:Young Adult
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D014364:Tryptophan; D006854:Hydrocortisone