Peptide YY secretion in morbidly obese patients before and after vertical banded gastroplasty

The Peptide YY (PYY) secretion pattern was assessed in morbidly obese (MO) patients before and after vertical banded gastroplasty (VBG). 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. 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. PYY concentration is lower in MO patients compared with non-obese. After VBG, PYY concentration gradually rises to the control levels.