title: Abnormal levels of neuropeptide Y and peptide YY in the colon in irritable bowel syndrome.
abstract: OBJECTIVE
  To assess the levels of gut peptides involved in gastrointestinal motor, secretory and sensory function in colonic biopsies in irritable bowel syndrome (IBS) patients and healthy controls.
  
  
  METHODS
  We studied 34 patients with IBS and 15 subjects without gastrointestinal symptoms. The predominant bowel pattern in the IBS patients was constipation in 17 patients (IBS-C) and diarrhoea in 17 patients (IBS-D). With radioimmunoassay, the levels of vasoactive intestinal peptide (VIP), substance P, neuropeptide Y (NPY) and peptide YY (PYY) were analysed in biopsies from the descending colon and ascending colon obtained during colonoscopy.
  
  
  RESULTS
  The IBS patients had lower levels of PYY in the descending colon than the controls, but the levels in the ascending colon did not differ. The NPY levels were lower in IBS-D than in IBS-C, both in the ascending colon and in the descending colon. Low levels of VIP were more common in IBS patients, but mean levels did not differ between groups. No group differences were observed for substance P. The levels of VIP, substance P and NPY were higher in the ascending colon than in the descending colon, whereas the opposite pattern was seen for PYY.
  
  
  CONCLUSIONS
  IBS patients demonstrate lower levels of PYY in the descending colon than controls. Colonic NPY levels differ between IBS subgroups based on the predominant bowel pattern. These findings may reflect the pathophysiology of IBS and the symptom variation within the IBS population.
authors.affiliation: Section of Gastroenterology, Department of Internal Medicine, Sahlgrenska University Hosptial, Göteborg, Sweden. magnus.simren@medicine.gu.se
authors.forename: Magnus
authors.initials: M
authors.lastname: Simrén
authors.forename: Per-Ove
authors.initials: PO
authors.lastname: Stotzer
authors.forename: Henrik
authors.initials: H
authors.lastname: Sjövall
authors.forename: Hasse
authors.initials: H
authors.lastname: Abrahamsson
authors.forename: Einar S
authors.initials: ES
authors.lastname: Björnsson
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy / Q000379:methods; D016022:Case-Control Studies; D003106:Colon / Q000737:chemistry*; D003109:Colonic Diseases, Functional / Q000150:complications / Q000378:metabolism*; D003248:Constipation / Q000209:etiology / Q000378:metabolism; D003967:Diarrhea / Q000209:etiology / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009478:Neuropeptide Y / Q000032:analysis*; D019894:Peptide YY / Q000032:analysis*; D013373:Substance P / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
chemical_list: D009478:Neuropeptide Y; D019894:Peptide YY; D013373:Substance P; D014660:Vasoactive Intestinal Peptide