Peptide YY3-36 and glucagon-like peptide-1 in functional dyspepsia. Secretion and role in symptom generation

The role of peptide YY3-36 (PYY3-36), glucagon-like peptide-1 (GLP-1), and glucose homoeostasis in symptom development in functional dyspepsia (FD) is unclear. The aim was to investigate postprandial changes in plasma PYY3-36, GLP-1, glucose and insulin, and the relationship between PYY3-36, GLP-1, dyspeptic symptoms, and satiety measurements.

Thirty-six patients with functional dyspepsia and 18 healthy controls consumed a liquid meal at two occasions. Firstly, a fixed amount of 250 mL (300 kcal) was consumed and gastric emptying was assessed using the paracetamol method. Secondly, participants drank 75 mL (90 kcal) per five min until maximal satiety. PYY3-36, GLP-1, glucose, and insulin concentrations were assessed. Satiety measures and dyspeptic symptoms were registered using visual analogue scales.

Gastric emptying, glucose, PYY3-36, and GLP-1 concentrations were similar in patients and controls. Patients with epigastric pain syndrome had higher postprandial insulin levels. Patients reported more satiety, nausea, and pain. Area under the curve (AUC) for GLP-1 correlated positively to nausea in patients and negatively to nausea in controls during a single meal. AUC for PYY3-36 correlated similarly to sensation of fullness in the two groups; however, the correlation was negative for the single meal and positive for the satiety test.

In epigastric pain syndrome, postprandial insulin secretion seems to be increased. Neither GLP-1 nor PYY3-36 secretion is altered in functional dyspepsia, but postprandial GLP-1 secretion seems to correlate with nausea and PYY3-36 to the sensation of fullness, and therefore, these hormones might be involved in symptom generation.