title: Evaluation of brain natriuretic peptide levels in hyperthyroidism and hypothyroidism.
abstract: BACKGROUND
  Brain natriuretic peptide (BNP) is secreted from the ventricular myocardium in response to volume expansion and pressure overload. Serum BNP levels are also affected by thyroid function status, which was mostly related to a direct stimulatory effect of thyroid hormones on the secretion of BNP. Although the diagnostic value of BNP in heart failure is undisputed, its value in the presence of the thyroid dysfunction has been recently questioned. The aim of this study was to evaluate the influence of thyroid dysfunction on BNP levels.
  
  
  METHODS
  Evaluation of 18 overt and 47 subclinical hyperthyroid patients together with 39 subclinical and 13 overt hypothyroid patients was carried out in a cross-sectional study. Thirty-three age-, sex- and body mass index (BMI)-matched control subjects were also included.
  
  
  RESULTS
  BNP levels were more than five times higher in hyperthyroid than euthyroid control subjects (P < 0.001). BNP levels were also higher in subclinical hyperthyroidism than euthyroid control subjects (P = 0.09). Correlation analysis revealed that free T4 and free T3 concentrations were associated with high serum BNP levels. The BNP level in patients with subclinical or overt hypothyroidism was similar to that of the controls.
  
  
  CONCLUSIONS
  The current study provides additional insight into the diagnostic value of BNP in the presence of coexistent thyroid dysfunction and demonstrates important independent effects of thyroid hormones upon BNP plasma concentrations.
authors.affiliation: Department of Internal Medicine, Division of Endocrinology and Metabolism, Baskent University Faculty of Medicine, Ankara, Turkey. dertaner@yahoo.com
authors.forename: Derun Taner
authors.initials: DT
authors.lastname: Ertugrul
authors.forename: Alptekin
authors.initials: A
authors.lastname: Gursoy
authors.forename: Mustafa
authors.initials: M
authors.lastname: Sahin
authors.forename: Asli Dogruk
authors.initials: AD
authors.lastname: Unal
authors.forename: Baris
authors.initials: B
authors.lastname: Pamuk
authors.forename: Zehra
authors.initials: Z
authors.lastname: Berberoglu
authors.forename: Semra
authors.initials: S
authors.lastname: Ayturk
authors.forename: Neslihan Bascil
authors.initials: NB
authors.lastname: Tutuncu
authors.forename: Nilgun Guvener
authors.initials: NG
authors.lastname: Demirag
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000209:etiology*; D006352:Heart Ventricles; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000150:complications* / Q000175:diagnosis*; D007037:Hypothyroidism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D020097:Natriuretic Peptide, Brain / Q000097:blood* / Q000378:metabolism; D011446:Prospective Studies; D013963:Thyroid Hormones / Q000502:physiology
chemical_list: D015415:Biomarkers; D013963:Thyroid Hormones; D020097:Natriuretic Peptide, Brain