title: Effect of gastric bypass on spontaneous growth hormone and ghrelin release profiles.
abstract: OBJECTIVE
  The purpose of this study was to analyze growth hormone (GH) concentrations in obese women before and after Roux-en-Y gastric bypass (RYGBP) and how resulting changes in weight, fat mass, ghrelin levels, and insulin sensitivity affect GH secretion.
  
  
  METHODS
  Blood was sampled at 20-minute intervals for 24 hours in 10 non-diabetic premenopausal severely obese women before and 6 months after RYGBP. GH concentrations were measured in all samples, and serum ghrelin was collected at five time-points.
  
  
  RESULTS
  After a 27% BMI drop (55.9 +/- 6.2 to 40.7 +/- 5.8 kg/m2), blunted GH profiles underwent partial recovery. Basal, postprandial, and mean ghrelin concentrations were not changed. A negative correlation was found between mean GH levels and insulin and homeostasis model assessment (p < 0.01). BMI accounted for 54% of GH variation.
  
  
  CONCLUSIONS
  Partial recovery of GH secretion after RYGBP-induced weight loss suggests that a blunted secretion is not a causal factor of obesity but a consequence of the obese state and does not seem to be ghrelin-level dependent.
authors.affiliation: Obesity and Metabolic Syndrome Unit, Endocrinology Service, Hospital das Clínicas, São Paulo University School of Medicine, São Paulo, Brazil. mmancini@usp.br
authors.forename: Marcio C
authors.initials: MC
authors.lastname: Mancini
authors.forename: Ana P A C
authors.initials: AP
authors.lastname: Costa
authors.forename: Maria Edna
authors.initials: ME
authors.lastname: de Melo
authors.forename: Cintia
authors.initials: C
authors.lastname: Cercato
authors.forename: Daniel
authors.initials: D
authors.lastname: Giannella-Neto
authors.forename: Arthur B
authors.initials: AB
authors.lastname: Garrido
authors.forename: Sten
authors.initials: S
authors.lastname: Rosberg
authors.forename: Kerstin
authors.initials: K
authors.lastname: Albertsson-Wikland
authors.forename: Sandra M F
authors.initials: SM
authors.lastname: Villares
authors.forename: Alfredo
authors.initials: A
authors.lastname: Halpern
mesh_terms: D000328:Adult; D001823:Body Composition; D001835:Body Weight / Q000502:physiology; D005260:Female; D015390:Gastric Bypass; D054439:Ghrelin; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008137:Longitudinal Studies; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000503:physiopathology / Q000601:surgery*; D036361:Peptide Hormones / Q000097:blood / Q000378:metabolism*; D019518:Postprandial Period / Q000502:physiology; D011446:Prospective Studies
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones; D013006:Growth Hormone