title: Adiponectin inhibits lipolysis in mouse adipocytes.
abstract: OBJECTIVE
  Adiponectin is an adipocyte-derived hormone that sensitizes insulin and improves energy metabolism in tissues. This study was designed to investigate the direct regulatory effects of adiponectin on lipid metabolism in adipocytes.
  
  
  METHODS
  Basal and hormone-stimulated lipolysis were comparatively analyzed using white adipose tissues or primary adipocytes from adiponectin gene knockout and control mice. To further study the underlying mechanisms through which adiponectin suppresses lipolysis, cultured 3T3-L1 adipocytes and adenovirus-mediated gene transduction were used.
  
  
  RESULTS
  Significantly increased lipolysis was observed in both adiponectin gene knockout mice and primary adipocytes from these mice. Hormone-stimulated glycerol release was inhibited in adiponectin-treated adipocytes. Adiponectin suppressed hormone-sensitive lipase activation without altering adipose triglyceride lipase and CGI-58 expression in adipocytes. Moreover, adiponectin reduced protein levels of the type 2 regulatory subunit RIIα of protein kinase A by reducing its protein stability. Ectopic expression of RIIα abolished the inhibitory effects of adiponectin on lipolysis in adipocytes.
  
  
  CONCLUSIONS
  This study demonstrates that adiponectin inhibits lipolysis in adipocytes and reveals a novel function of adiponectin in lipid metabolism in adipocytes.
authors.affiliation: Department of Pediatrics, University of California San Diego, La Jolla, California, USA.
authors.forename: Liping
authors.initials: L
authors.lastname: Qiao
authors.forename: Brice
authors.initials: B
authors.lastname: Kinney
authors.forename: Jerome
authors.initials: J
authors.lastname: Schaack
authors.forename: Jianhua
authors.initials: J
authors.lastname: Shao
mesh_terms: D041721:3T3-L1 Cells; D017667:Adipocytes / Q000166:cytology* / Q000378:metabolism*; D052242:Adiponectin / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit / Q000235:genetics / Q000378:metabolism; D004041:Dietary Fats / Q000009:adverse effects; D008066:Lipolysis / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009765:Obesity / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism
chemical_list: D052242:Adiponectin; C499919:Adipoq protein, mouse; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D004041:Dietary Fats