title: Visfatin is an adipokine, but it is not regulated by thiazolidinediones.
abstract: BACKGROUND
  Visfatin was recently reported to be expressed in human adipose tissue and to exert insulin-mimicking effects.
  
  
  OBJECTIVE
  The objective of this study was to examine whether visfatin is a true adipokine and is expressed in isolated fat cells. We also examined whether visfatin is regulated by thiazolidinediones and, thus, can contribute to the ability of these agents to improve insulin sensitivity.
  
  
  METHODS
  This was an open-labeled drug therapy trial.
  
  
  METHODS
  This study was performed at a university hospital.
  
  
  METHODS
  Seven newly diagnosed and previously untreated type 2 diabetic patients and six healthy individuals with reduced insulin sensitivity participated in the study.
  
  
  METHODS
  Pioglitazone therapy (30-45 mg/d) was given for 3-4 wk.
  
  
  METHODS
  Serum and adipose tissue mRNA levels of visfatin and adiponectin were the main outcome measures.
  
  
  RESULTS
  Visfatin mRNA is expressed in both adipose tissue and isolated adipocytes. Treatment with thiazolidinediones for 3-4 wk did not alter the gene expression or circulating levels of visfatin in either nondiabetic or the diabetic individuals, whereas adiponectin increased significantly.
  
  
  CONCLUSIONS
  The present study shows that visfatin is a true adipokine, but it is not regulated by TZD and, thus, is unlikely to contribute to the insulin-sensitizing actions of these drugs.
authors.affiliation: Lundberg Laboratory for Diabetes Research, Department of Internal Medicine, Sahlgrenska University Hospital, SE-413 45 Goteborg, Sweden. ann.hammarstedt@medic.gu.se.
authors.forename: Ann
authors.initials: A
authors.lastname: Hammarstedt
authors.forename: Jussi
authors.initials: J
authors.lastname: Pihlajamäki
authors.forename: Victoria
authors.initials: V
authors.lastname: Rotter Sopasakis
authors.forename: Silvia
authors.initials: S
authors.lastname: Gogg
authors.forename: Per-Anders
authors.initials: PA
authors.lastname: Jansson
authors.forename: Markku
authors.initials: M
authors.lastname: Laakso
authors.forename: Ulf
authors.initials: U
authors.lastname: Smith
mesh_terms: D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D015309:Glucose Clamp Technique; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D054409:Nicotinamide Phosphoribosyltransferase; D012016:Reference Values; D045162:Thiazolidinediones / Q000627:therapeutic use*
chemical_list: D016207:Cytokines; D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D054409:Nicotinamide Phosphoribosyltransferase; C085455:nicotinamide phosphoribosyltransferase, human