title: Serum ghrelin levels in response to glucose load in obese subjects post-gastric bypass surgery.
abstract: OBJECTIVE
  We sought to elucidate further the mechanisms leading to weight loss after gastric bypass (GBP) surgery in morbidly obese individuals. Ghrelin is a gastroenteric appetite-stimulating peptide hormone, fasting levels of which decrease with increasing adiposity and increase with diet-induced weight loss. In addition, ghrelin levels rapidly decline postprandially.
  
  
  METHODS
  We measured serum ghrelin responses to a 75-g oral glucose tolerance test (OGTT) in 6 subjects who had undergone GBP surgery 1.5 +/- 0.7 years before testing and compared these responses with 6 obese subjects about to undergo GBP surgery, 6 obese nonsurgical subjects (matched for BMI to the post-GBP surgical group), and 5 lean subjects.
  
  
  RESULTS
  Despite weight loss induced by the GBP surgery, fasting serum ghrelin levels were significantly lower in the post-GBP surgery group than in the lean subject (by 57%) or pre-GBP surgery (by 45%) group. Serum ghrelin levels during the OGTT were significantly lower in postoperative than in lean, obese pre-GBP surgical, or obese nonsurgical subjects. The magnitude of the decline in serum ghrelin levels between 0 and 120 minutes post-OGTT was significantly smaller in postoperative (by 62%), obese pre-GBP surgical (by 80%), or obese nonsurgical (by 69%) subjects in comparison with lean subjects.
  
  
  CONCLUSIONS
  Serum ghrelin levels in response to OGTT are lower in subjects post-GBP surgery than in either lean or obese subjects. Tonically low serum ghrelin levels may be involved in the mechanisms inducing sustained weight loss after GBP surgery.
authors.affiliation: Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Tritos
authors.forename: Edward
authors.initials: E
authors.lastname: Mun
authors.forename: Anne
authors.initials: A
authors.lastname: Bertkau
authors.forename: Rebecca
authors.initials: R
authors.lastname: Grayson
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Maratos-Flier
authors.forename: Allison
authors.initials: A
authors.lastname: Goldfine
mesh_terms: D000328:Adult; D005260:Female; D015390:Gastric Bypass; D054439:Ghrelin; D005947:Glucose / Q000008:administration & dosage*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery; D036361:Peptide Hormones / Q000097:blood*; D011184:Postoperative Period; D015431:Weight Loss / Q000502:physiology*
chemical_list: D054439:Ghrelin; D007328:Insulin; D036361:Peptide Hormones; D005947:Glucose