The role of long chain fatty acids in regulating food intake and cholecystokinin release in humans.
OBJECTIVE
The mechanism of intraduodenal fat induced inhibition of food intake is still unclear. Therefore, we tested the ability of duodenal fatty acids to suppress food intake at a lunchtime meal; in addition, we were interested to test if these effects were mediated by cholecystokinin (CCK) A receptors.


METHODS
Three sequential double blind, three period crossover studies were performed in 12 healthy males each: (1) subjects received intraduodenal fat with or without 120 mg of tetrahydrolipstatin, an inhibitor of gastrointestinal lipases, or saline; (2) volunteers received intraduodenal long chain fatty acids, medium chain fatty acids, or saline; (3) subjects received long chain fatty acids or saline together with concomitant intravenous infusions of saline or loxiglumide, a specific CCK-A receptor antagonist. The effect of these treatments on food intake and feelings of hunger was quantified.


RESULTS
Intraduodenal fat perfusion significantly (p<0.05) reduced calorie intake. Inhibition of fat hydrolysis abolished this effect. Only long chain fatty acids significantly (p<0.05) decreased calorie intake, whereas medium chain fatty acids were ineffective. Infusion of loxiglumide abolished the effect of long chain fatty acids.


CONCLUSIONS
Generation of long chain fatty acids through hydrolysis of fat is a critical step for fat induced inhibition of food intake; the signal is mediated via CCK-A receptors.
Matzinger
D
D
Department of Research and Division of Gastroenterology, University Hospital, CH-4031 Basel, Switzerland.
Degen
L
L
Drewe
J
J
Meuli
J
J
Duebendorfer
R
R
Ruckstuhl
N
N
D'Amato
M
M
Rovati
L
L
Beglinger
C
C
D000328:Adult; D002766:Cholecystokinin / Q000378:metabolism*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004386:Duodenum / Q000378:metabolism*; D004435:Eating / Q000502:physiology*; D002149:Energy Intake; D005227:Fatty Acids / Q000502:physiology*; D006727:Hormone Antagonists / Q000494:pharmacology; D006801:Humans; D006815:Hunger / Q000502:physiology; D008297:Male; D011377:Proglumide / Q000031:analogs & derivatives / Q000494:pharmacology; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors / Q000502:physiology
D005227:Fatty Acids; D006727:Hormone Antagonists; D011949:Receptors, Cholecystokinin; C053737:loxiglumide; D002766:Cholecystokinin; D011377:Proglumide