title: Inverse relationship of peripheral thyrotropin-stimulating hormone levels to brain activity in mood disorders.
abstract: OBJECTIVE
  The author's goal was to investigate relationships between peripheral thyroid hormone levels and cerebral blood flow (CBF) and cerebral glucose metabolism in affectively ill patients.
  
  
  METHODS
  Medication-free inpatients with major depression or bipolar disorder were studied with oxygen-15 water and positron emission tomography (PET) to measure CBF (N = 19) or with [18F] fluorodeoxyglucose and PET to measure cerebral glucose metabolism (N = 29). Linear regression was used to correlate global CBF and cerebral glucose metabolism with serum thyrotropin-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), and free T4 concentrations. Statistical parametric mapping was used to correlate regional CBF and cerebral glucose metabolism with these thyroid indexes. Post hoc t tests were used to further explore the relationships between serum TSH and global CBF and cerebral glucose metabolism.
  
  
  RESULTS
  Serum TSH was inversely related to both global and regional CBF and cerebral glucose metabolism. These relationships persisted in the cerebral glucose metabolism analysis and, to a lesser extent, in the CBF analysis after severity of depression had been controlled for. In contrast, no significant relationships were observed between T3, T4, or free T4 and global or regional CBF and cerebral glucose metabolism.
  
  
  CONCLUSIONS
  These data suggest that peripheral TSH (putatively the best marker of thyroid status) is inversely related to global and regional CBF and cerebral glucose metabolism. These findings indicate relationships between thyroid and cerebral activity that could provide mechanistic hypotheses for thyroid contributions to primary and secondary mood disorders and the psychotropic effects of thyroid axis manipulations.
authors.affiliation: National Institutes of Health, Bethesda, Md. 20892, USA.
authors.forename: L B
authors.initials: LB
authors.lastname: Marangell
authors.forename: T A
authors.initials: TA
authors.lastname: Ketter
authors.forename: M S
authors.initials: MS
authors.lastname: George
authors.forename: P J
authors.initials: PJ
authors.lastname: Pazzaglia
authors.forename: A M
authors.initials: AM
authors.lastname: Callahan
authors.forename: P
authors.initials: P
authors.lastname: Parekh
authors.forename: P J
authors.initials: PJ
authors.lastname: Andreason
authors.forename: B
authors.initials: B
authors.lastname: Horwitz
authors.forename: P
authors.initials: P
authors.lastname: Herscovitch
authors.forename: R M
authors.initials: RM
authors.lastname: Post
mesh_terms: D000328:Adult; D001714:Bipolar Disorder / Q000175:diagnosis / Q000503:physiopathology; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D003847:Deoxyglucose / Q000031:analogs & derivatives / Q000378:metabolism; D003866:Depressive Disorder / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D010104:Oxygen Radioisotopes; D012044:Regression Analysis; D013972:Thyrotropin / Q000097:blood* / Q000502:physiology; D013974:Thyroxine / Q000097:blood; D014055:Tomography, Emission-Computed; D014284:Triiodothyronine / Q000097:blood
chemical_list: D010104:Oxygen Radioisotopes; D014284:Triiodothyronine; D019788:Fluorodeoxyglucose F18; D013972:Thyrotropin; D003847:Deoxyglucose; D005947:Glucose; D013974:Thyroxine