Fat-induced ileal brake in humans: a dose-dependent phenomenon correlated to the plasma levels of peptide YY.
BACKGROUND
Upper gastrointestinal motility is regulated by the presence of nutrients in the distal gut. The present study evaluated whether lipid-induced ileal brake on gastric emptying (1) can be elicited by low fat concentrations; (2) is a dose-dependent phenomenon; and (3) is related to gastrointestinal peptide release.


METHODS
Seven patients were studied in the defunctionalized stage of total colectomy, on three separate occasions. On each study day, patients ate a meal labeled in the solid component; 30 minutes later, one of the following solutions was randomly infused into the ileal pouch: 0.9% saline, 2% oleic acid, and 20% oleic acid. Plasma concentrations of peptide YY (PYY), enteroglucagon, neurotensin, and motilin were measured.


RESULTS
Both oleic acid solutions slowed gastric emptying compared with saline (P < 0.001), the effect being dose dependent (P < 0.001). Ileal infusions did not modify neurotensin and enteroglucagon levels but induced a dose-dependent increase of PYY (P < 0.01) and a borderline decrease of motilin (P = 0.05) levels. Slower rates of gastric emptying were related to increased plasma concentrations of PYY (r = 0.615; P < 0.05).


CONCLUSIONS
This study shows that (1) the ileal brake on gastric emptying can be evoked by low doses of lipids in the distal ileum; (2) the delay of gastric emptying is related to the release of PYY; and (3) both phenomena are dose dependent.
Pironi
L
L
Institute of Internal Medicine and Gastroenterology, S. Orsola-Malpighi Hospital, University of Bologna, Italy.
Stanghellini
V
V
Miglioli
M
M
Corinaldesi
R
R
De Giorgio
R
R
Ruggeri
E
E
Tosetti
C
C
Poggioli
G
G
Morselli Labate
A M
AM
Monetti
N
N
D000328:Adult; D003082:Colectomy; D004305:Dose-Response Relationship, Drug; D005260:Female; D005746:Gastric Emptying / Q000502:physiology; D005769:Gastrointestinal Motility / Q000502:physiology*; D004763:Glucagon-Like Peptides / Q000097:blood / Q000502:physiology; D006801:Humans; D007082:Ileum / Q000502:physiology*; D008055:Lipids / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009037:Motilin / Q000097:blood / Q000502:physiology; D009496:Neurotensin / Q000097:blood / Q000502:physiology; D019894:Peptide YY; D010455:Peptides / Q000097:blood* / Q000502:physiology; D013997:Time Factors
D008055:Lipids; D010455:Peptides; D019894:Peptide YY; D009496:Neurotensin; D009037:Motilin; D004763:Glucagon-Like Peptides