title: Inflammation inhibits GPR81 expression in adipose tissue.
abstract: OBJECTIVE
  The aim of this study was to examine the expression of G protein-coupled receptor 81 (GPR81) in mouse adipose tissue in response to inflammatory stimuli. GPR81 is activated by lactate resulting in the inhibition of lipolysis.
  
  
  METHODS
  Mice were injected with saline, lipopolysaccharide (LPS), zymosan, or turpentine, N = 5 per group. 3T3-L1 adipocytes were treated with tumor necrosis factor alpha, interleukin (IL)-l beta, IL-6, or interferon gamma.
  
  
  METHODS
  GPR81 expression levels were measured by real-time PCR and statistical significance was determined by Student's t test.
  
  
  RESULTS
  LPS resulted in a marked decrease in GPR81 mRNA level in mouse adipose tissue in C57BL/6 and OuJ mice, an effect that was not observed in HeJ mice, which have a mutation in TLR4. Zymosan and turpentine also decreased adipose tissue GPR81 expression. Cytokine treatment of 3T3-L1 adipocytes had no effect on GPR81 expression. GPR81 expression was decreased in ob/ob mice, an animal model of type 2 diabetes that is characterized by inflammation.
  
  
  CONCLUSIONS
  Inflammation decreases the expression of GPR81 in adipose tissue.
authors.affiliation: Metabolism Section (111F), Department of Veterans Affairs Medical Center, University of California San Francisco, 4150 Clement Street, San Francisco, CA 94121, USA. kenneth.feingold@ucsf.edu
authors.forename: Kenneth R
authors.initials: KR
authors.lastname: Feingold
authors.forename: Arthur
authors.initials: A
authors.lastname: Moser
authors.forename: Judy K
authors.initials: JK
authors.lastname: Shigenaga
authors.forename: Carl
authors.initials: C
authors.lastname: Grunfeld
mesh_terms: D041721:3T3-L1 Cells / Q000166:cytology; D017667:Adipocytes / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D016207:Cytokines / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D007249:Inflammation / Q000378:metabolism*; D007371:Interferon-gamma / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000096:biosynthesis; D015850:Interleukin-6 / Q000096:biosynthesis; D008066:Lipolysis; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D043562:Receptors, G-Protein-Coupled / Q000096:biosynthesis*; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D016207:Cytokines; C529424:Hcar1 protein, mouse; D053583:Interleukin-1beta; D015850:Interleukin-6; D043562:Receptors, G-Protein-Coupled; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D007371:Interferon-gamma