title: Adipokine expression in brown and white adipocytes in response to hypoxia.
abstract: BACKGROUND
  Adipose tissue has emerged as an important endocrine regulator by secreting hormones referred to as adipokines. Recent studies showed that adipose tissue considerably responds to hypoxia. Although the impact of white adipose tissue on regulative processes is established, the importance of brown adipose tissue in adults has emerged just recently.
  
  
  METHODS
  Brown (BA) and white adipocytes (WA) were cultured either in the presence of chemical hypoxia-mimetics or under hypoxic atmosphere of 1% oxygen. Expression of hypoxia-inducible factor 1α (HIF- 1α) was assessed by western blot. The expression levels of several known HIF-1α-regulated proteins [vascular endothelial growth factor (VEGF), leptin, adiponectin, and angiotensinogen (AGT)] were quantified.
  
  
  RESULTS
  Both chemical hypoxia-mimetics and physical hypoxia led to increased nuclear HIF-1α expression and to decreased cytoplasmatic adiponectin in both cell types. In contrast, VEGF and AGT expression did not change upon hypoxic stimulation. Leptin was exclusively detectable in WA, while uncoupling-protein 1 (UCP-1) was expressed in BA only.
  
  
  CONCLUSIONS
  WA and BA are sensitive to hypoxia, in which HIF-1α expression is induced. Protein expression of adiponectin is hypoxia-dependent, whereas AGT, VEGF, leptin, and UCP-1 expression do not change secondary to hypoxia.
authors.affiliation: Department of Gastroenterology and Hepatology, University of Essen, University Hospital Essen, Hufelandstrasse 55, 45122 Essen, Germany. alexander.wree@uk-essen.de
authors.forename: A
authors.initials: A
authors.lastname: Wree
authors.forename: A
authors.initials: A
authors.lastname: Mayer
authors.forename: S
authors.initials: S
authors.lastname: Westphal
authors.forename: A
authors.initials: A
authors.lastname: Beilfuss
authors.forename: A
authors.initials: A
authors.lastname: Canbay
authors.forename: R R
authors.initials: RR
authors.lastname: Schick
authors.forename: G
authors.initials: G
authors.lastname: Gerken
authors.forename: P
authors.initials: P
authors.lastname: Vaupel
mesh_terms: D052438:Adipocytes, White / Q000166:cytology / Q000378:metabolism*; D054392:Adipokines / Q000378:metabolism*; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D016587:Antimutagenic Agents / Q000633:toxicity; D002478:Cells, Cultured; D003035:Cobalt / Q000633:toxicity; D003676:Deferoxamine / Q000633:toxicity; D000860:Hypoxia / Q000139:chemically induced / Q000378:metabolism*; D015151:Immunoblotting; D020738:Leptin / Q000378:metabolism; D051379:Mice; D017262:Siderophores / Q000633:toxicity
chemical_list: D054392:Adipokines; D016587:Antimutagenic Agents; D020738:Leptin; D017262:Siderophores; D003035:Cobalt; C018021:cobaltous chloride; D003676:Deferoxamine