title: Thyroid Hormone Activates Brown Adipose Tissue and Increases Non-Shivering Thermogenesis--A Cohort Study in a Group of Thyroid Carcinoma Patients.
abstract: OBJECTIVE
  Thyroid hormone receptors are present on brown adipose tissue (BAT), indicating a role for thyroid hormone in the regulation of BAT activation. The objective of this study was to examine the effect of thyroid hormone withdrawal followed by thyroid hormone in TSH-suppressive dosages, on energy expenditure and brown adipose tissue activity.
  
  
  METHODS
  This study was a longitudinal study in an academic center, with a follow-up period of 6 months. Ten patients with well-differentiated thyroid carcinoma eligible for surgical treatment and subsequent radioactive iodine ablation therapy were studied in a hypothyroid state after thyroidectomy and in a subclinical hyperthyroid state (TSH-suppression according to treatment protocol). Paired two-tailed t-tests and linear regression analyses were used.
  
  
  RESULTS
  Basal metabolic rate (BMR) was significantly higher after treatment with synthetic thyroid hormone (levothyroxine) than in the hypothyroid state (BMR 3.8 ± 0.5 kJ/min versus 4.4 ± 0.6 kJ/min, P = 0.012), and non-shivering thermogenesis (NST) significantly increased from 15 ± 10% to 25 ± 6% (P = 0.009). Mean BAT activity was significantly higher in the subclinical hyperthyroid state than in the hypothyroid state (BAT standard uptake value (SUVMean) 4.0 ± 2.9 versus 2.4 ± 1.8, P = 0.039).
  
  
  CONCLUSIONS
  Our study shows that higher levels of thyroid hormone are associated with a higher level of cold-activated BAT.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT02499471.
authors.affiliation: MUMC+, Department of Human Biology, Maastricht, the Netherlands.|MUMC+, Department of General Surgery, Maastricht, the Netherlands.
authors.forename: Evie P M
authors.initials: EP
authors.lastname: Broeders
authors.affiliation: MUMC+, Department of Human Biology, Maastricht, the Netherlands.|St. Franciscus Gasthuis, Department of Surgery, Rotterdam, the Netherlands.|MUMC+, Department of General Surgery, Maastricht, the Netherlands.
authors.forename: Guy H E J
authors.initials: GH
authors.lastname: Vijgen
authors.affiliation: MUMC+, Department of Endocrinology, Maastricht, the Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: Havekes
authors.affiliation: MUMC+, Department of General Surgery, Maastricht, the Netherlands.
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Bouvy
authors.affiliation: MUMC+, Department of Nuclear Medicine, Maastricht, the Netherlands.|Department of Nuclear Medicine, University Hospital RWTH Aachen University, Aachen, Germany.
authors.forename: Felix M
authors.initials: FM
authors.lastname: Mottaghy
authors.affiliation: MUMC+, Department of Endocrinology, Maastricht, the Netherlands.
authors.forename: Marleen
authors.initials: M
authors.lastname: Kars
authors.affiliation: MUMC+, Department of Endocrinology, Maastricht, the Netherlands.
authors.forename: Nicolaas C
authors.initials: NC
authors.lastname: Schaper
authors.affiliation: MUMC+, Department of Human Biology, Maastricht, the Netherlands.
authors.forename: Patrick
authors.initials: P
authors.lastname: Schrauwen
authors.affiliation: MUMC+, Department of Nuclear Medicine, Maastricht, the Netherlands.
authors.forename: Boudewijn
authors.initials: B
authors.lastname: Brans
authors.affiliation: MUMC+, Department of Human Biology, Maastricht, the Netherlands.
authors.forename: Wouter D
authors.initials: WD
authors.lastname: van Marken Lichtenbelt
mesh_terms: D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism*; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D022722:Thermogenesis / Q000187:drug effects*; D013963:Thyroid Hormones / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D013964:Thyroid Neoplasms / Q000378:metabolism*
chemical_list: D013963:Thyroid Hormones