title: Impact of prolonged low-grade physical training on the in vivo glucocorticoid sensitivity and on glucocorticoid receptor-alpha mRNA levels of obese adolescents.
abstract: OBJECTIVE
  Healthy individuals present variable responses of the hypothalamic-pituitary-adrenal (HPA) axis induced by different patterns of physical training. The aim of this study was to evaluate whether prolonged low-grade physical training influences the HPA axis and also glucocorticoid receptor-alpha (GRalpha) mRNA levels in mononuclear cells of obese adolescents.
  
  
  METHODS
  We studied 19 patients with BMI above the 95th percentile (male:female ratio 7:12) aged from 9.5 to 15.5 years. Patients underwent a 12-week physical exercise program. Before and after exercise, in vivo glucocorticoid sensitivity was determined by employing a very-low-dose intravenous dexamethasone suppression test, and in vitro GRalpha mRNA levels were evaluated by quantitative real-time PCR.
  
  
  RESULTS
  After exercise there was a trend to reduce the in vivo glucocorticoid sensitivity (p = 0.071) and a significant increase in GRalpha mRNA levels (p = 0.025).
  
  
  CONCLUSIONS
  For this subset of obese adolescents, prolonged low-grade physical training tended to reduce glucocorticoid sensitivity. The discrepancy of cortisol response to dexamethasone and the GRalpha mRNA measurement suggest a post-receptor phenomenon or should be related to target tissue-specific differences in glucocorticoid sensitivity. Future studies should address the adaptive GRalpha mRNA during different exercise protocols, and also the correlation of pituitary sensitivity with glucocorticoid target tissue sensitivity.
authors.affiliation: Pediatric Endocrinology Unit, Pediatric Department of the Irmandade da Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil. ceclau@terra.com.br
authors.forename: Cláudia Dutra Costantin
authors.initials: CD
authors.lastname: Faria
authors.forename: Roberta Borges
authors.initials: RB
authors.lastname: Castro
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Longui
authors.forename: Cristiane
authors.initials: C
authors.lastname: Kochi
authors.forename: Vera Lúcia Perino
authors.initials: VL
authors.lastname: Barbosa
authors.forename: Tatiane
authors.initials: T
authors.lastname: Sousa E Silva
authors.forename: Mylene Neves
authors.initials: MN
authors.lastname: Rocha
authors.forename: Murilo Rezende
authors.initials: MR
authors.lastname: Melo
authors.forename: Osmar
authors.initials: O
authors.lastname: Monte
mesh_terms: D000293:Adolescent; D001786:Blood Glucose; D001823:Body Composition; D003907:Dexamethasone / Q000494:pharmacology; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D009765:Obesity / Q000235:genetics / Q000378:metabolism* / Q000628:therapy*; D018579:Patient Selection; D010809:Physical Fitness / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D001786:Blood Glucose; D007328:Insulin; D012333:RNA, Messenger; D011965:Receptors, Glucocorticoid; C411470:glucocorticoid receptor alpha; D003907:Dexamethasone