Exogenous prolactin-releasing peptide's orexigenic effect is associated with hypothalamic neuropeptide Y in chicks.
Exogenous administration of prolactin-releasing peptide (PrRP) exerts anorexigenic effects in rats while causing orexigenic effects in chicks. While the central mechanism mediating PrRP's effect on food intake in rodents is somewhat understood, in chicks information is lacking. Therefore, this study was designed to elucidate the hypothalamic mechanism of PrRP induction of hunger perception in chicks. Chicks that received intracerebroventricular (ICV) injections of PrRP dose-dependently increased their food intake with no effect on water intake or whole blood glucose concentration. The threshold of food intake stimulation was as low as 3pmol, thus as compared to other neuropeptides PrRP is exceptionally potent. The mRNA abundance of several appetite-associated neuropeptide genes was quantified and hypothalamic neuropeptide Y (NPY) mRNA was increased in PrRP-injected chicks. Therefore, the orexigenic effects of PrRP may be associated with increased NPY-ergic tone. These results provide insight into the evolutionary aspects of appetite regulation during the course of divergent evolution of mammals and birds.
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Guoqing
G
Wang
Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, Japan.
Tetsuya
T
Tachibana
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Elizabeth R
ER
Gilbert
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA. Electronic address: macline2@vt.edu.
Mark A
MA
Cline
D000818:Animals; D001069:Appetite Regulation / Q000187:drug effects*; D001786:Blood Glucose / Q000187:drug effects; D002645:Chickens / Q000502:physiology*; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D007276:Injections, Intraventricular; D009478:Neuropeptide Y / Q000378:metabolism*; D056690:Prolactin-Releasing Hormone / Q000008:administration & dosage / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism
D001786:Blood Glucose; D009478:Neuropeptide Y; D056690:Prolactin-Releasing Hormone; D012333:RNA, Messenger
Chick; Food intake; Hypothalamus; Prolactin-releasing peptide