Glucagon-Like Peptide-1, Peptide YY, Hunger, and Satiety after Gastric Bypass Surgery in Morbidly Obese Subjects

TLDR

Weight loss mechanisms after Roux‑en‑Y gastric bypass are poorly understood. The study aimed to evaluate changes in active GLP‑1 and total PYY after RYGBP and their association with hunger and satiety. A prospective study measured GLP‑1, PYY, hunger, and satiety responses to a standardized liquid meal in nine obese, normal‑glucose‑tolerant subjects before and six weeks after RYGBP. Six weeks post‑surgery, GLP‑1 and PYY responses were significantly higher, accompanied by reduced fasting and post‑prandial hunger and increased satiety, yet no significant correlation between hormonal changes and appetite measures was observed, suggesting RYGBP enhances these gut hormones and may contribute to appetite suppression.

Abstract

The mechanisms underlying weight loss after Roux-en-Y gastric bypass (RYGBP) are not well understood.The objective of the study was to assess the changes in active glucagon-like peptide 1 (GLP-1) and total peptide YY (PYY) after RYGBP and examine their relationship with changes in hunger and satiety.This was a prospective study on the changes in active GLP-1, PYY, hunger, and satiety in response to a standardized test meal in nine normal-glucose-tolerant obese subjects [body mass index (BMI) 47.4 +/- 6.1 kg/m(2)] before and 6 wk after RYGBP.Before surgery, meal ingestion failed to stimulate GLP-1 and PYY secretion. Six weeks after surgery, despite subjects still being markedly obese (BMI 43.6 +/- 7.8 kg/m(2)), the area under the curve(0-120') of GLP-1 and of PYY in response to the standardized test meal were significantly elevated (P < 0.05 and P < 0.01, respectively). These hormonal responses were significantly larger (P < 0.01) than those observed in a group matched for the BMI attained 6 wk after surgery. The 2.9 +/- 1.2- and 1.6 +/- 1.9-fold increase, respectively, in the area under the curve(0-120') of GLP-1 and PYY were accompanied by a significant decrease in fasting (P < 0.05) and postprandial hunger (P = 0.05) and a significant increase in satiety (P < 0.05) after meal intake. Nevertheless, a significant correlation between changes in the hormonal and eating behavior parameters was not found.Our data show that RYGBP is associated with an improvement in the active GLP-1 and total PYY response to a liquid-meal intake. Moreover, we provide circumstantial evidence for a potential role of these gastrointestinal hormones on the decreased appetite after RYGBP.