Gonadotropin-inhibiting hormone stimulates feeding behavior in chicks.
Neuropeptides containing a C-terminal Arg-Phe-NH2 motif (RFamide peptides) are suggested to be involved in the control of feeding behavior in both invertebrates and vertebrates. Gonadotropin-inhibitory hormone (GnIH) is the first identified avian RFamide peptide that inhibits gonadotropin release from the pituitary. The GnIH precursor encodes one GnIH and its related peptides (GnIH-RP-1 and -RP-2) that shared the same C-terminal motif, Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa = Leu or Gln) (LPXRFamide). GnIH neurons are localized in the paraventricular nucleus, with their fibers visible in multiple brain locations including the median eminence and brainstem. In this study, we therefore investigated the action of GnIH and its related peptides on feeding behavior. Intracerebroventricular (ICV) injection of GnIH, GnIH-RP-1 and GnIH-RP-2 significantly stimulated food intake in chicks. The chicken pentapeptide LPLRFamide, a degraded C-terminus of GnIH and GnIH-RP-1, did not stimulate feeding thereby demonstrating the importance of the N-terminus of GnIH and its related peptides for the orexigenic effect. Anti-GnIH antiserum suppressed appetite induced by fasting, but did not modify feeding under ad libitum conditions. The present study suggests that GnIH and its related peptides act as endogenous orexigenic factors in the brain of chicks.
Laboratory of Advanced Animal and Marine Bioresources, Graduate School of Bioresource and Bioenvironmental Science, Kyushu University, Fukuoka 812-8581, Japan. tetsu@brs.kyushu-u.ac.jp
Tetsuya
T
Tachibana
Momoka
M
Sato
Hirokazu
H
Takahashi
Kazuyoshi
K
Ukena
Kazuyoshi
K
Tsutsui
Mitsuhiro
M
Furuse
D000595:Amino Acid Sequence; D000818:Animals; D030161:Avian Proteins / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D002645:Chickens; D005247:Feeding Behavior / Q000187:drug effects* / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007028:Hypothalamic Hormones / Q000235:genetics / Q000276:immunology / Q000494:pharmacology*; D007106:Immune Sera / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000235:genetics / Q000494:pharmacology; D013739:Testosterone / Q000097:blood
D030161:Avian Proteins; D007028:Hypothalamic Hormones; D007106:Immune Sera; D009842:Oligopeptides; C413752:gonadotropin-inhibitory hormone, Coturnix japonica; C042219:leucyl-prolyl-leucyl-arginyl-phenylalaninamide; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone