title: Elevated serum levels of free triiodothyronine in adolescent boys with gynaecomastia compared with controls.
abstract: OBJECTIVE
  Pubertal gynaecomastia is a frequent phenomenon occurring in 20-40% of otherwise healthy adolescent boys. Little is known about the aetiology of pubertal gynaecomastia. Markedly elevated thyroid hormone levels in adults with hyperthyroidism are associated with gynaecomastia.
  
  
  METHODS
  A cross-sectional examination of 444 healthy boys with and without pubertal gynaecomastia.
  
  
  METHODS
  We evaluated TSH, triiodothyronine (T3), thyroxine (T4), free T4 and free T3 in a cohort of healthy boys with and without pubertal gynaecomastia.
  
  
  RESULTS
  Boys with gynaecomastia had significantly higher serum free T3, even after correction for age, BMI and pubertal stage. After inclusion of IGF1 in the model the differences disappeared. TSH, T4, free T4 and T3 did not differ between the groups.
  
  
  CONCLUSIONS
  We speculate that the GH/IGF1 axis and thyroid hormones interact and influence the development of pubertal gynaecomastia.
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark mikkel.grunnet.mieritz@regionh.dk.
authors: Mikkel G
authors: MG
authors: Mieritz
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Kaspar
authors: K
authors: Sorensen
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Lise
authors: L
authors: Aksglaede
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Annette
authors: A
authors: Mouritsen
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Casper P
authors: CP
authors: Hagen
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Linda
authors: L
authors: Hilsted
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Anna-Maria
authors: AM
authors: Andersson
authors: Departments of Growth and ReproductionSection 5064Clinical BiochemistryRigshospitalet, Faculty of Medical and Health Sciences, University of Copenhagen, DK-2100 Copenhagen, Denmark.
authors: Anders
authors: A
authors: Juul
mesh_terms: D000293:Adolescent; D003430:Cross-Sectional Studies; D006177:Gynecomastia / Q000097:blood*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D011627:Puberty / Q000502:physiology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood*
chemical_list: C583557:IGF1 protein, human; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D013972:Thyrotropin; D013974:Thyroxine