YY Peptide (PYY)
Overview
YY peptide, or peptide YY (PYY), is a 36-amino acid gut hormone released postprandially from L-cells in the distal ileum and colon. It acts as an incretin and appetite suppressant by binding Y2 receptors in the hypothalamus to reduce food intake and inhibit gastric emptying and pancreatic secretion. Low PYY levels are associated with obesity and type 2 diabetes, while elevated levels occur after bariatric surgery or protein-rich meals; abnormal secretion contributes to metabolic dysregulation. Clinically, PYY measurement helps evaluate postprandial responses, assess bariatric surgery outcomes, and research appetite regulation and energy homeostasis.
Clinical Use Cases
- Evaluation of appetite regulation in obesity and eating disorders.
- Assessment of metabolic changes after bariatric surgery (e.g., Roux-en-Y gastric bypass).
- Investigation of type 2 diabetes pathophysiology and incretin axis dysfunction.
- Research into short bowel syndrome and malabsorption effects on gut hormones.
- Monitoring response to GLP-1 receptor agonists or dietary interventions.
Specimen Types
- Plasma (preferred, with protease inhibitors).
- Serum (less stable).
Measurement Methods
- Radioimmunoassay (RIA).
- Enzyme-linked immunosorbent assay (ELISA).
- Liquid chromatography-mass spectrometry (LC-MS/MS).
- Multiplex bead immunoassays.
Test Preparation and Influencing Factors
- Fasting baseline samples; measure postprandially for meal response.
- Recent meals (especially high-fat/protein) stimulate PYY release.
- Stress, exercise, and circadian rhythm affect secretion.
- DPP-4 inhibitors prolong circulating active PYY(3-36).
- Sample processing critical: chill immediately, add DPP-IV inhibitor and Trasylol.
- Obesity reduces basal and postprandial PYY levels.
Synonyms
- Peptide YY.
- PYY3-36 (major circulating form).
- Gut hormone PYY.