title: Medical and surgical treatments for obesity have opposite effects on peptide YY and appetite: a prospective study controlled for weight loss.
abstract: BACKGROUND
  The effects of medical and surgical treatments for obesity on peptide YY (PYY) levels, in patients with similar weight loss, remain unclear.
  
  
  OBJECTIVE
  The objective of the study was to assess PYY and appetite before and after Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), and medical treatment (MED).
  
  
  METHODS
  This was a prospective, controlled, nonrandomized study.
  
  
  METHODS
  The study was conducted at the Departments of Nutrition and Digestive Surgery at a university hospital.
  
  
  METHODS
  PARTICIPANTS included three groups of eight patients with similar body mass indexes (RYGB 37.8 +/- 0.8, SG 35.3 +/- 0.7, and MED 39.1 +/- 1.7 kg/m(2), P = NS) and eight lean controls (body mass index 21.7 +/- 0.7 kg/m(2)).
  
  
  METHODS
  Total plasma PYY, hunger, and satiety visual analog scales in fasting and after ingestion of a standard test meal were measured.
  
  
  RESULTS
  At baseline there were no differences in the area under the curve (AUC) of PYY, hunger, or satiety in obese groups. Two months after the interventions, RYGB, SG, and MED groups achieved similar weight loss (17.7 +/- 3, 14.9 +/- 2.4, 16.6 +/- 4%, respectively, P = NS). PYY AUC increased in RYGB (P < 0.001) and SG (P < 0.05) and did not change in MED. PYY levels decreased at fasting, 30 min, and 180 min after a standard test meal in MED (P < 0.05). Hunger AUC decreased in RYGB (P < 0.05). Satiety AUC increased in RYGB (P < 0.05) and SG (P < 0.05). Appetite did not change in MED. PYY AUC correlated with satiety AUC (r = 0.35, P < 0.05).
  
  
  CONCLUSIONS
  RYGB and SG increased PYY and reduced appetite. MED failed to produce changes. Different effects occur despite similar weight loss. This suggests that the weight-loss effects of these procedures are enhanced by an increase in PYY and satiety.
authors.affiliation: Department of Nutrition, Diabetes, and Metabolism, Pontificia Universidad Católica de Chile, Marcoleta 367, 6510260 Santiago, Chile. jpvalder@uc.cl
authors.forename: Juan P
authors.initials: JP
authors.lastname: Valderas
authors.forename: Verónica
authors.initials: V
authors.lastname: Irribarra
authors.forename: Camilo
authors.initials: C
authors.lastname: Boza
authors.forename: Rolando
authors.initials: R
authors.lastname: de la Cruz
authors.forename: Yessica
authors.initials: Y
authors.lastname: Liberona
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Acosta
authors.forename: Macarena
authors.initials: M
authors.lastname: Yolito
authors.forename: Alberto
authors.initials: A
authors.lastname: Maiz
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D015992:Body Mass Index; D004035:Diet Therapy; D015444:Exercise; D005260:Female; D005743:Gastrectomy; D015390:Gastric Bypass; D006801:Humans; D006815:Hunger / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000628:therapy*; D018579:Patient Selection; D019894:Peptide YY / Q000097:blood*; D011446:Prospective Studies; D011863:Radioimmunoassay; D012044:Regression Analysis; D012527:Satiation / Q000502:physiology*; D013997:Time Factors; D015431:Weight Loss / Q000502:physiology*
chemical_list: D019894:Peptide YY