Cholinergic regulation of ghrelin and peptide YY release may be impaired in obesity.
OBJECTIVE
Ghrelin and peptide YY (PYY) are both hormones derived from the gastrointestinal tract involved in appetite regulation. The cholinergic part of the vagal nerve is involved in the regulation of glucose and insulin. The aim of this study was to examine the effects of the cholinergic antagonist atropine on ghrelin, PYY, glucose, and insulin under basal conditions and after meal ingestion in lean and obese subjects.


METHODS
Eight lean and eight obese subjects were included in a randomized, double-blind, placebo-controlled crossover study with 4 study days in randomized order (atropine/placebo +/- breakfast). Plasma ghrelin, PYY, insulin, and glucose were measured. Hunger and satiety feelings were rated on a 10-cm visual analog scale.


RESULTS
In lean individuals, atropine led to a decrease in ghrelin concentrations comparable and nonadditive with breakfast ingestion and a significant decrease in both basal and meal-induced PYY concentrations. In obese subjects, atropine did not significantly change ghrelin or PYY concentrations, whereas it induced a comparable increase in heart rate and meal-induced glucose concentrations in the two study groups. Only lean, not obese, subjects experienced sustained feelings of satiety after breakfast.


CONCLUSIONS
The impaired cholinergic regulation of the postprandial drop in ghrelin concentrations and rise in PYY concentrations might be part of the deregulated food intake in obese subjects.
Clinical Division of Endocrinology and Metabolism, Department ofMedicine III, Medical University of Vienna, Vienna, Austria. christina.maier@meduniwien.ac.at
Christina
C
Maier
Michaela
M
Riedl
Greisa
G
Vila
Peter
P
Nowotny
Michael
M
Wolzt
Martin
M
Clodi
Bernhard
B
Ludvik
Anton
A
Luger
D000328:Adult; D001285:Atropine / Q000008:administration & dosage*; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight; D002799:Cholinergic Fibers / Q000187:drug effects / Q000378:metabolism; D018592:Cross-Over Studies; D004435:Eating / Q000187:drug effects; D005260:Female; D041981:Gastrointestinal Tract / Q000294:innervation / Q000378:metabolism; D054439:Ghrelin / Q000097:blood*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000188:drug therapy* / Q000378:metabolism*; D010276:Parasympatholytics / Q000008:administration & dosage*; D019894:Peptide YY / Q000097:blood*; D019518:Postprandial Period / Q000187:drug effects; D012528:Satiety Response / Q000187:drug effects; D014630:Vagus Nerve / Q000187:drug effects / Q000378:metabolism
D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D010276:Parasympatholytics; D019894:Peptide YY; D001285:Atropine