Effects of obestatin on energy balance and growth hormone secretion in rodents.
Ghrelin stimulates food intake and adiposity and thereby increases body weight (BW) in rodents after central as well as peripheral administration. Recently, it was discovered that the gene precursor of ghrelin encoded another secreted and bioactive peptide named obestatin. First reports appeared to demonstrate that this peptide requires an amidation for its biological activity and acts through the orphan receptor, GPR-39. Obestatin was shown to have actions opposite to ghrelin on food intake, BW, and gastric emptying. In the present study, we failed to observe any effect of obestatin on food intake, BW, body composition, energy expenditure, locomotor activity, respiratory quotient, or hypothalamic neuropeptides involved in energy balance regulation. In agreement with the first report, we were unable to find any effect of obestatin on GH secretion in vivo. Moreover, we were unable to find mRNA expression of GPR-39, the putative obestatin receptor, in the hypothalamus of rats. Therefore, the results presented here do not support a role of the obestatin/GPR-39 system in the regulation of energy balance.
Nogueiras
Rubén
R
Department of Pharmacology, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany.
Pfluger
Paul
P
Tovar
Sulay
S
Arnold
Myrtha
M
Mitchell
Sharon
S
Morris
Amanda
A
Perez-Tilve
Diego
D
Vázquez
Maria J
MJ
Wiedmer
Petra
P
Castañeda
Tamara R
TR
DiMarchi
Richard
R
Tschöp
Matthias
M
Schurmann
Annette
A
Joost
Hans-Georg
HG
Williams
Lynda M
LM
Langhans
Wolfgang
W
Diéguez
Carlos
C
D000818:Animals; D004435:Eating / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D054439:Ghrelin; D013006:Growth Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D036361:Peptide Hormones / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism; D014628:Vagotomy; D015430:Weight Gain / Q000187:drug effects / Q000502:physiology
C512928:GPR39 protein, mouse; D054439:Ghrelin; D036361:Peptide Hormones; D043562:Receptors, G-Protein-Coupled; C512328:obestatin, mouse; D013006:Growth Hormone