title: Plasma bile acids are associated with energy expenditure and thyroid function in humans.
abstract: OBJECTIVE
  Animal studies implicate a role of bile acids (BA) in thyroid-regulated energy expenditure (EE) via activation of the TGR-5/adenylate cyclase/deiodinase type 2 pathway. Here we investigated these possible associations in humans.
  
  
  METHODS
  EE, BA, and thyroid hormone status were assessed in 10 healthy subjects and eight patients with liver cirrhosis at baseline and after oral nutrition. In cirrhosis, blood was additionally sampled from the mesenteric vein and the radial artery.
  
  
  RESULTS
  At baseline, BA and EE related positively (r = 0.648, P = 0.048 in healthy subjects; r = 0.833, P = 0.010 in cirrhosis; r = 0.556, P =0.017 in all), with the highest correlation with deoxycholic acid levels. The respiratory quotient associated negatively to baseline BA (all, r = -0.639, P = 0.004). Postprandially, serum TSH decreased in both groups (P < 0.05 each). In cirrhosis, the decrease of TSH after 60 min correlated to the meal-stimulated BA increase (r = -0.762, P = 0.028). To assess the mechanism involved, we studied a single human TSHoma and TαT1 mouse thyrotrope cells. In TSHoma cells, TGR-5 was predominantly expressed cytoplasmically, and in vitro stimulation with BA did not substantially alter cAMP or deiodinase type 2.
  
  
  CONCLUSIONS
  Our data support a role of BA in human energy metabolism and in thyroid hormone control. Even though no convincing response to BA was demonstrated in TSHoma and TαT1 cells, the TSH decrease after a nutritional challenge suggests an interaction of BA on the set point of the thyroid axis.
authors.affiliation: Department of Gastroenterology, Hepatology, Endocrinology, and Nutrition, Klinikum Bremen Mitte, St. Juergen Strasse 1, D-28177 Bremen, Germany. johann.ockenga@klinikum-bremen-mitte.de
authors.forename: Johann
authors.initials: J
authors.lastname: Ockenga
authors.forename: Luzia
authors.initials: L
authors.lastname: Valentini
authors.forename: Tatjana
authors.initials: T
authors.lastname: Schuetz
authors.forename: Franziska
authors.initials: F
authors.lastname: Wohlgemuth
authors.forename: Silja
authors.initials: S
authors.lastname: Glaeser
authors.forename: Ajmal
authors.initials: A
authors.lastname: Omar
authors.forename: Esmatollah
authors.initials: E
authors.lastname: Kasim
authors.forename: Daniel
authors.initials: D
authors.lastname: duPlessis
authors.forename: Karen
authors.initials: K
authors.lastname: Featherstone
authors.forename: Julian R
authors.initials: JR
authors.lastname: Davis
authors.forename: Uwe J F
authors.initials: UJ
authors.lastname: Tietge
authors.forename: Thomas
authors.initials: T
authors.lastname: Kroencke
authors.forename: Heike
authors.initials: H
authors.lastname: Biebermann
authors.forename: Josef
authors.initials: J
authors.lastname: Köhrle
authors.forename: Georg
authors.initials: G
authors.lastname: Brabant
mesh_terms: D000328:Adult; D001647:Bile Acids and Salts / Q000097:blood*; D001706:Biopsy; D002153:Calorimetry, Indirect; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000473:pathology / Q000601:surgery; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D019168:Portasystemic Shunt, Transjugular Intrahepatic; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000502:physiology*
chemical_list: D001647:Bile Acids and Salts