Peptide YY Levels Are Elevated After Gastric Bypass Surgery

Abstract

CHAN, JEAN L., EDWARD C. MUN, VIOLETA STOYNEVA, CHRISTOS S. MANTZOROS, AND ALLISON B. GOLDFINE. Peptide YY levels are elevated after gastric bypass surgery. Obesity. 2006;14:194 -198. Objective: Mechanisms that promote effective and sustained weight loss in persons who have undergone Rouxen-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. Research Methods and Procedures: PYY and ghrelin levels after a 75-gram oral glucose tolerance test were measured in 6 morbidly obese patients 1.5 Ϯ 0.7 (SE) years after gastric bypass compared with 5 lean and 12 obese controls. Results: After substantial body weight loss (36.8 Ϯ 3.6%) induced by gastric bypass, the PYY response to an oral glucose tolerance test was significantly higher than in controls (p ϭ 0.01). PYY increased ϳ10-fold after a 75-gram glucose load to a peak of 303.0 Ϯ 37.0 pg/mL at 30 minutes (p ϭ 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 ϳ2-fold, which was only borderline significant. Ghrelin levels decreased in a symmetric but opposite fashion to that of PYY. Discussion: 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.

Ghrelin and PYY3−36 in gastrectomized and vagotomized patients: relations with appetite, energy intake and resting energy expenditure

“…The small sample size may have contributed to the apparent lack of response. It is of note that negligible postprandial PYY responses to a mixed meal were also reported in other studies (Chan et al, 2006;Lomenick et al, 2009).…”

“…Intravenous infusions of PYY in humans have been shown to decrease subsequent food intake (Degen et al, 2005). Both a continued suppression of plasma ghrelin concentrations and an early PYY response to nutrients have been suggested to be involved in body weight loss and maintenance after Roux-en-Y gastric bypass for the treatment of obesity (Chan et al, 2006).…”

Ghrelin in gastrointestinal diseases and disorders: A possible role in the pathophysiology and clinical implications (Review)

“…Following Roux-Y gastric bypass, the plasma level of deacyl-ghrelin increases in non-diabetic obese patients, but not in diabetic patients (55)(56)(57). Patients operated by Roux-en-Y gastric bypass show an early and greater postprandial suppression of ghrelin level than patients operated by gastric banding (58).…”

Individually timing high-protein preloads has no effect on daily energy intake, peptide YY and glucagon-like peptide-1

“…In support of the important role of gut peptides in the control of energy balance are the numerous reports showing the early exaggerated secretion of both peptide YY and GLP-1 following obesity surgery (Naslund et al, 1997a, b;Korner et al, 2005Korner et al, , 2006Chan et al, 2006;Morinigo et al, 2006;le Roux et al, 2006a). There is at least one report showing the more direct implication of these peptides in the control of feeding.…”