The satiety hormone peptide YY as a regulator of appetite.
More PYY => Less Food Eaten
New study Lap band => DECREASE in PYY => May drive patients to try to eat more!!!
PYY reduction in obese subjects is associated with decreased satiety and increased food intake. Obese subjects have a PYY deficiency that reduces satiety and leads to excess food intake.
After gastric Bypass PYY is significantly elevated accompanied by a significant decrease in hunger and a significant increase in satiety (P < 0.05) after meal intake.
www.ncbi.nlm.nih.gov/pubmed/18441153by RP Vincent – 2008
Unknown hormonal and neural satiety signals are thought to drive sustainable weight loss following laparoscopic adjustable gastric banding (LAGB).
A cross-sectional study examined 17 postoperative individuals who had already achieved a mean of 28% LAGB-induced weight loss (range, 10-38%). A prospective study assessed plasma PP and PYY meal responses in 16 obese individuals prior to LAGB.
Fasting PYY levels, however, were significantly lower in the postoperative group compared to the group tested pre-operatively, or the BMI-matched controls (-30%, p = 0.03).
PYY appears reduced in proportion to weight loss following LAGB, possibly representing attempted orexigenic homeostatic compensation.