Effects of PYY1-36 and PYY3-36 on appetite, energy intake, energy expenditure, glucose and fat metabolism in obese and lean subjects

Effects of PYY1-36 and PYY3-36 on appetite, energy intake, energy expenditure, glucose and fat metabolism in obese and lean subjects. Am J Physiol Endocrinol Metab 292: E1062-E1068, 2007. First published December 5, 2006; doi:10.1152/ajpendo.00450.2006. - Peptide YY (PYY)(3-36) has been shown to produce dramatic reductions in energy intake (EI), but no human data exist regarding energy expenditure (EE), glucose and fat metabolism. Nothing is known regarding PYY1-36. To compare effects of PYY1-36 and PYY3-36 on appetite, EI, EE, insulin, glucose and free fatty acids (FFA) concentrations, 12 lean and 12 obese males participated in a blinded, randomized, crossover study with 90-min infusions of saline, 0.8 pmol center dot kg(-1)center dot min(-1) PYY1-36 and PYY3-36. Only four participants completed PYY3-36 infusions because of nausea. Subsequently, six lean and eight obese participants completed 0.2 pmol center dot kg(-1)center dot min(-1) PYY3-36 and 1.6 pmol center dot kg(-1)center dot min(-1)center dot PYY1-36 infusions. PYY3-36 at 0.8 pmol center dot kg(-1)center dot min(-1) produced reduced EI, lower ratings of well-being, increases in FFA, postprandial glucose (only 0.8 pmol center dot kg(-1)center dot min(-1) PYY3-36) and insulin concentrations, as well as heart rate and EE (only 0.8 pmol center dot kg(-1)center dot min(-1) PYY3-36). PYY1-36 at 1.6 pmol center dot kg(-1)center dot min(-1) produced increased heart rate and postprandial insulin response. Ratings of appetite were opposite with infusions of 0.8 and 1.6 pmol center dot kg(-1)center dot min(-1) PYY1-36 and seemed to depend on subjects being lean or obese. PYY3-36 caused increased thermogenesis, lipolysis, postprandial insulin and glucose responses, suggestive of increased sympathoadrenal activity. PYY1-36 had no effect on EI and no clear effects on appetite but resulted in increased heart rate and postprandial insulin response. However, highest tolerable dose of PYY1-36 was probably not reached in the present study.