Peptide yy kinetics and effects on blood pressure and circulating pancreatic and gastrointestinal hormones and metabolites in man

Peptide YY (PYY) is a 36 amino acid peptide produced by mucosal endocrine cells of the ileum and colon which inhibits acid secretion and intestinal transit in man. To assess its effects on metabolites and digestive hormones PYY was infused into 18 fasting normal subjects at three dose levels (0.06, 0.19, and 0.57 pmol kg⁻¹ min⁻¹), each for a period of 1 h. During the infusions mean plasma PYY levels increased by 8, 25, and 73 pmol/liter, respectively.The mean disappearance half−time on stopping the infusions was 9.2 ± 0.4 (SEM) min. The mean MCR was 7.3 ° 0.7 ml kg⁻¹ min⁻¹ and the apparent volume of distributionwas calculated to be 94 ° 9 ml kg⁻¹ During the highest dose infusion there was a significant increase in both systolic and diastolic blood pressure, of 8.6 ° 3.7 mmHg (P < 0.05) and 10.9 ° 3.0 mmHg (P < 0.01), respectively. PYY caused a significant50% reduction in plasma pancreatic polypeptide concentrations (P < 0.05) and a 55% reduction in circulating motilin levels (P < 0.05). PYY had no significant effect on circulating concentrationsof insulin, glucagon, gastrin, gastric inhibitory peptide, neurotensin, enteroglucagon, or vasoactive intestinal peptide. PYY also had no significant effect on circulating concentrations of glucose, lactate, glycerol, or nonesterified fatty acids. This recently discovered human intestinal hormonal peptidethus has significant effects both on gastrointestinal hormones (motilin and pancreatic polypeptide) and blood pressure in man, but appears not to influence glucose or lipid metabolism.