Peptide YY levels are elevated after gastric bypass surgery.
OBJECTIVE
Mechanisms that promote effective and sustained weight loss in persons who have undergone Roux-en-Y gastric bypass surgery are incompletely understood but may be mediated, in part, by changes in appetite. Peptide YY (PYY) is a gut-derived hormone with anorectic properties. We sought to determine whether gastric bypass surgery alters PYY levels or response to glucose.


METHODS
PYY and ghrelin levels after a 75-gram oral glucose tolerance test were measured in 6 morbidly obese patients 1.5 +/- 0.7 (SE) years after gastric bypass compared with 5 lean and 12 obese controls.


RESULTS
After substantial body weight loss (36.8 +/- 3.6%) induced by gastric bypass, the PYY response to an oral glucose tolerance test was significantly higher than in controls (p = 0.01). PYY increased approximately 10-fold after a 75-gram glucose load to a peak of 303.0 +/- 37.0 pg/mL at 30 minutes (p = 0.03) and remained significantly higher than fasting levels for all subsequent time-points. In contrast, PYY levels in obese and lean controls increased to a peak of approximately 2-fold, which was only borderline significant. Ghrelin levels decreased in a symmetric but opposite fashion to that of PYY.


CONCLUSIONS
Gastric bypass results in a more robust PYY response to caloric intake, which, in conjunction with decreased ghrelin levels, may contribute to the sustained efficacy of this procedure. The findings provide further evidence for a role of gut-derived hormones in mediating appetite changes after gastric bypass and support further efforts to determine whether PYY(3-36) replacement could represent an effective therapy for obesity.
Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Jean L
JL
Chan
Edward C
EC
Mun
Violeta
V
Stoyneva
Christos S
CS
Mantzoros
Allison B
AB
Goldfine
D019440:Anti-Obesity Agents / Q000097:blood / Q000627:therapeutic use; D001066:Appetite / Q000502:physiology; D019540:Area Under Curve; D002149:Energy Intake / Q000502:physiology; D005260:Female; D015390:Gastric Bypass; D054439:Ghrelin; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000601:surgery*; D036361:Peptide Hormones / Q000097:blood / Q000627:therapeutic use; D019894:Peptide YY / Q000097:blood*; D015431:Weight Loss / Q000502:physiology
D019440:Anti-Obesity Agents; D054439:Ghrelin; D036361:Peptide Hormones; D019894:Peptide YY