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Evidence for a stimulatory action of melanin-concentrating hormone on luteinising hormone release involving MCH1 and melanocortin-5 receptors.
- Source :
-
Journal of neuroendocrinology [J Neuroendocrinol] 2006 Mar; Vol. 18 (3), pp. 157-67. - Publication Year :
- 2006
-
Abstract
- The present series of studies aimed to further our understanding of the role of melanin-concentrating hormone (MCH) neurones in the central regulation of luteinising hormone (LH) release in the female rat. LH release was stimulated when MCH was injected bilaterally into the rostral preoptic area (rPOA) or medial preoptic area (mPOA), but not when injected into the zona incerta (ZI), of oestrogen-primed ovariectomised rats. In rats that were steroid-primed to generate a surge-like release of LH, MCH administration into the ZI blocked this rise in LH release: no such effect occurred when MCH was injected into the rPOA or mPOA. In vitro, MCH stimulated gonadotrophin-releasing hormone (GnRH) release from hypothalamic explants. Double-label immunohistochemistry showed GnRH-immunoreactive neurones in the vicinity of and intermingled with immunoreactive MCH processes. MCH is the endogenous ligand of the MCH type 1 receptor (MCH1-R). Previously, we have shown a role for melanocortin-5 receptors (MC5-R) in the stimulatory action of MCH, so we next investigated the involvement of both MCH1-R and/or MC5-R in mediating the actions of MCH on GnRH and hence LH release. The stimulatory action of MCH in the rPOA was inhibited by administration of antagonists for either MCH1-R or MC5-R. However, in the mPOA, the action of MCH was blocked only by the MC5-R antagonist. LH release was stimulated by an agonist for MC5-R injected into the rPOA or mPOA; this was blocked by the MC5-R antagonist but not the MCH1-R antagonist. These results indicate that both MCH1-R and MC5-R are involved in the central control of LH release by MCH.
- Subjects :
- Animals
Female
Gonadotropin-Releasing Hormone metabolism
Hypothalamus metabolism
Immunohistochemistry
Ovariectomy
Rats
Rats, Wistar
Receptors, Melanocortin
Hypothalamic Hormones pharmacology
Luteinizing Hormone metabolism
Melanins pharmacology
Pituitary Hormones pharmacology
Receptors, Corticotropin physiology
Receptors, Somatostatin physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0953-8194
- Volume :
- 18
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Journal of neuroendocrinology
- Publication Type :
- Academic Journal
- Accession number :
- 16454799
- Full Text :
- https://doi.org/10.1111/j.1365-2826.2005.01397.x