title: Early changes in ghrelin following Roux-en-Y gastric bypass: influence of vagal nerve functionality?
abstract: BACKGROUND
  Roux-en-Y gastric bypass (RYGBP) effectively produces massive weight reduction, improving health in morbidly obese patients. The mechanisms for the weight loss, and the fate of the excluded gastric mucosa, are not fully clarified. To what extent the appetite-stimulating gastric peptide ghrelin is affected remains controversial.
  
  
  METHODS
  Circulating concentrations of ghrelin, pancreatic polypeptide (PP), pepsinogen I (PGI) and gastrin were examined in 15 morbidly obese patients (median BMI 45 kg/m2) preoperatively, and on days 1, 2, 4, 6 and at months 1, 6 and 12 after RYGBP.
  
  
  RESULTS
  Ghrelin levels fell on postoperative day 1 and increased after 1 month to preoperative levels, and rose further at 6 and 12 months. PP concentrations decreased on day 1 and subsequently returned to preoperative levels. PGI levels peaked transiently the first days after surgery and subsequently declined to lower than preoperative levels. Gastrin levels were gradually reduced postoperatively.
  
  
  CONCLUSIONS
  Ghrelin and PP fall transiently after surgery, possibly due to vagal dysfunction, and ultimately, as weight loss ensues, ghrelin secretion increases to higher than preoperative levels. The RYBGP procedure affects the gastric mucosa, as reflected by a transient increase in circulating PGI, and subsequently, the mucosa in the excluded stomach is at rest, as shown by low levels of PGI and gastrin.
authors.affiliation: Department of Surgery, University Hospital, S-751 85 Uppsala, Sweden. magnus.sundbom@surgsci.uu.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Sundbom
authors.forename: Camilla
authors.initials: C
authors.lastname: Holdstock
authors.forename: Britt Eden
authors.initials: BE
authors.lastname: Engström
authors.forename: F Anders
authors.initials: FA
authors.lastname: Karlsson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D015390:Gastric Bypass; D005753:Gastric Mucosa / Q000294:innervation / Q000502:physiology; D018530:Gastric Stump / Q000294:innervation*; D005755:Gastrins / Q000097:blood; D054439:Ghrelin; D006801:Humans; D008297:Male; D008875:Middle Aged; D010191:Pancreatic Polypeptide / Q000097:blood; D020116:Pepsinogen A / Q000097:blood; D036361:Peptide Hormones / Q000097:blood*; D011184:Postoperative Period; D011863:Radioimmunoassay; D013997:Time Factors; D014630:Vagus Nerve / Q000502:physiology*; D015431:Weight Loss / Q000502:physiology*
chemical_list: D005755:Gastrins; D054439:Ghrelin; D036361:Peptide Hormones; D010191:Pancreatic Polypeptide; D020116:Pepsinogen A