The postprandial secretion of peptide YY and in obesity is differentially increased after gastric bypass versus sleeve gastrectomy.

OBJECTIVES

Peptide tyrosine tyrosine (PYY) exists as two species, PYY and PYY , with distinct effects on insulin secretion and appetite regulation. The detailed effects of bariatric surgery on PYY and PYY secretion are not known as previous studies have used nonspecific immunoassays to measure total PYY. Our objective was to characterize the effect of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) on fasting and postprandial PYY and PYY secretion using a newly developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay.

DESIGN AND SUBJECTS

Observational study in 10 healthy nonobese volunteers and 30 participants with obesity who underwent RYGB (n = 24) or SG (n = 6) at the Imperial Weight Centre [NCT01945840]. Participants were studied using a standardized mixed meal test (MMT) before and 1 year after surgery. The outcome measures were PYY and PYY concentrations.

RESULTS

Presurgery, the fasting and postprandial levels of PYY and PYY were low, with minimal responses to the MMT, and these did not differ from healthy nonobese volunteers. The postprandial secretion of both PYY and PYY at 1 year was amplified after RYGB, but not SG, with the response being significantly higher in RYGB compared with SG.

CONCLUSIONS

There appears to be no difference in PYY secretion between nonobese and obese volunteers at baseline. At 1 year after surgery, RYGB, but not SG, is associated with increased postprandial secretion of PYY and PYY , which may account for long-term differences in efficacy and adverse effects between the two types of surgery.