title: Chronic glucocorticoid treatment enhances lipogenic activity in visceral adipocytes of male Wistar rats.
abstract: OBJECTIVE
  Glucocorticoid (GC) in excess promotes the redistribution of adipose tissue from peripheral to central sites of the body. In this study, we characterized an experimental condition of prolonged GC excess and investigated its effect on the lipogenic metabolism in white adipose tissue.
  
  
  METHODS
  Twenty male Wistar rats were divided into control (CON) and dexamethasone-treated (DEX) groups. DEX group received dexamethasone (0.25 mg kg(-1) day(-1) ) during 4 weeks, while CON group received saline. Animals were killed and subcutaneous (SC), retroperitoneal (RP) and mesenteric (MS) fat pads were excised, weighed and processed for adipocyte isolation, morphometric cell analysis and incorporation of glucose into lipids.
  
  
  RESULTS
  The treatment effectively blocked hypothalamic-pituitary-adrenal axis, as verified by a 58% decrease in plasma corticosterone levels and 19% atrophy in adrenal glands in DEX group. Animals from DEX group presented insulin resistance, glucose intolerance, dyslipidaemia and increased insulin and leptin plasma levels and hypertrophied adipocytes. They showed increased lipogenesis in RP and MS depots, with increased incorporation of glucose into fatty acids of triacylglycerol. Increased activity of lipogenic enzymes ATP-citrate lyase, fatty acid synthase, glucose-6-phosphate dehydrogenase and malic was only seen in the MS depot in DEX group, while gene expression of these enzymes was enhanced in SC and MS fat depots.
  
  
  CONCLUSIONS
  The adaptations promoted by GC treatment in adipose metabolism seemed to be mainly due to the increased activity of enzymes that supply the NADPH required for lipogenesis than to the increase in enzymes that more directly deal with fatty acid synthesis itself.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo - USP, São Paulo, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Chimin
authors.forename: T da S M
authors.initials: Tda S
authors.lastname: Farias
authors.forename: F L
authors.initials: FL
authors.lastname: Torres-Leal
authors.forename: A
authors.initials: A
authors.lastname: Bolsoni-Lopes
authors.forename: A B
authors.initials: AB
authors.lastname: Campaña
authors.forename: S
authors.initials: S
authors.lastname: Andreotti
authors.forename: F B
authors.initials: FB
authors.lastname: Lima
mesh_terms: D052438:Adipocytes, White / Q000187:drug effects*; D000818:Animals; D003907:Dexamethasone / Q000009:adverse effects*; D005938:Glucocorticoids / Q000009:adverse effects*; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D050152:Intra-Abdominal Fat / Q000187:drug effects*; D050155:Lipogenesis / Q000187:drug effects*; D008297:Male; D010913:Pituitary-Adrenal System / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone
keywords: adipose tissue; glucocorticoids; lipogenesis