Differential regulation of plasma obestatin and ghrelin by meal intake and the cholinergic system in lean, but not obese individuals.
BACKGROUND
Obestatin is cosecreted with and stemming from the same precursor as ghrelin and is apparently involved in energy metabolism. Relatively little is known about the regulation of obestatin release.


OBJECTIVE
The regulation of obestatin release and obestatin-to-ghrelin ratios by meal intake and the cholinergic system were studied in lean and obese subjects.


METHODS
We conducted a randomized, double-blind, placebo-controlled, crossover study with 4 study days in eight obese (body mass index >30 kg/m(2)) and eight matched lean (body mass index <25 kg/m(2)) healthy subjects (two males and six females per group) at a University Clinical Research Unit.


METHODS
Atropine (1 mg iv) was administered alone and in combination with breakfast (550 kcal) intake, or placebo (isotonic saline) alone and in combination with breakfast.


METHODS
We measured plasma obestatin and obestatin/ghrelin ratios.


RESULTS
Both obestatin and ghrelin/obestatin ratios decreased significantly from baseline by either atropine or meal intake in lean individuals, with the two effects adding up on the combined atropine/breakfast day. In contrast, there were no statistically significant differences in obese subjects, who also showed significantly greater association between ghrelin and obestatin values than their lean counterparts.


CONCLUSIONS
Obestatin and ghrelin release is differentially regulated by meal intake and the cholinergic system in lean individuals. This regulation is impaired in obesity.
Maier
Christina
C
Department of Clinical Endocrinology and Metabolism, University Clinics of Medicine III, Medical University of Vienna, Vienna, Austria. Christina.maier@meduniwien.ac.at
Riedl
Michaela
M
Vila
Greisa
G
Wolzt
Michael
M
Clodi
Martin
M
Ludvik
Bernhard
B
Luger
Anton
A
D000328:Adult; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology; D002799:Cholinergic Fibers / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004435:Eating / Q000502:physiology*; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D008297:Male; D009765:Obesity / Q000097:blood* / Q000378:metabolism; D010275:Parasympathetic Nervous System / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D010276:Parasympatholytics / Q000008:administration & dosage / Q000494:pharmacology; D036361:Peptide Hormones / Q000097:blood*; D010919:Placebos; D013851:Thinness / Q000097:blood* / Q000378:metabolism
D054439:Ghrelin; D010276:Parasympatholytics; D036361:Peptide Hormones; D010919:Placebos; C505799:obestatin, human; D001285:Atropine