Stimulation effect of galanin-like peptide (GALP) on luteinizing hormone-releasing hormone-mediated luteinizing hormone (LH) secretion in male rats.
Galanin-like peptide (GALP) is a recently isolated hypothalamic peptide which has sequence homology to galanin and binds to galanin receptors with high affinity. It has been shown that GALP neurons are localized in the arcuate nucleus and that GALP-immunoreactive fibers are in close apposition with LHRH neurons in the medial preoptic area (MPA). In the present study, we found that intracerebroventricular (icv) administration of GALP increased the plasma LH level but did not change the levels of other hormones. Concomitantly, accumulation of c-Fos protein was dramatically increased in the nuclei of LHRH-positive cells in the MPA by icv GALP administration. Furthermore, the GALP-induced plasma LH response was completely abolished by pretreatment with Cetrorelix, a LHRH receptor antagonist. On the other hand, GALP did not affect the release of LH, FSH, TSH, ACTH, GH or PRL directly from dispersed rat pituitary cells in vitro. These results strongly suggest a role for GALP in the control of gonadotropin secretion through a hypothalamic mechanism involving the release of LHRH.
Matsumoto
H
H
Discovery Research Laboratories I, Pharmaceutical Discovery Research Division, Takeda Chemical Industries Ltd., Tsukuba, Ibaraki 300-4293, Japan.
Noguchi
J
J
Takatsu
Y
Y
Horikoshi
Y
Y
Kumano
S
S
Ohtaki
T
T
Kitada
C
C
Itoh
T
T
Onda
H
H
Nishimura
O
O
Fujino
M
M
D000818:Animals; D019004:Galanin / Q000494:pharmacology; D044089:Galanin-Like Peptide; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology*; D006727:Hormone Antagonists / Q000494:pharmacology; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011966:Receptors, LHRH / Q000037:antagonists & inhibitors
D044089:Galanin-Like Peptide; D006727:Hormone Antagonists; D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; D019004:Galanin; D007986:Luteinizing Hormone; C062876:cetrorelix