Peptide YY Secretion in Morbidly Obese Patients Before and After Vertical Banded Gastroplasty

Background: The Peptide YY (PYY) secretion pattern was assessed in morbidly obese (MO) patients before and after vertical banded gastroplasty (VBG). Methods: 12 MO patients (10 women, 2 men) age 29-62 years, BMI 50.7 ± 9.6 kg/m², treated with a VBG were studied. Before surgery, blood samples were taken in basal conditions of fasting and 10, 15, 20, 30 and 60 min after the ingestion of a semiliquid test meal. This was repeated in the same patients 6 and 12 months after VBG. Blood samples were also taken from 6 healthy non-obese subjects as controls. PYY plasma concentration was measured by radioimmunoassay with I¹²⁵. Results: There were statistically significant differences between the preoperative PYY concentration in MO patients compared to controls. After a VBG, PYY concentration varied significantly compared to the preoperative levels.There was no significant difference between the PYY concentrations in the MO patients after VBG and the controls. Conclusion: PYY concentration is lower in MO patients compared with non-obese. After VBG, PYY concentration gradually rises to the control levels.