Alarin 6-25Cys antagonizes alarin-specific effects on food intake and luteinizing hormone secretion.

Autor: Fraley GS; Department of Biology & Neuroscience Program, Hope College, Holland, MI 49423, USA. fraley@hope.edu, Leathley E, Nickols A, Gerometta E, Coombs E, Colton S, Gallemore S, Lindberg A, Kofler B
Jazyk: angličtina
Zdroj: Neuropeptides [Neuropeptides] 2013 Feb; Vol. 47 (1), pp. 37-41. Date of Electronic Publication: 2012 Sep 23.
DOI: 10.1016/j.npep.2012.08.007
Abstrakt: Previous data from our labs and from others have demonstrated that intracerebroventricular (ICV) injection of alarin has orexigenic activity and significantly increases plasma luteinizing hormone (LH) secretion in a gonadotropin-releasing hormone (GnRH) dependent manner. The purpose of the current experiments was to determine if the amino acids at the amino-terminal end of the alarin peptide are critical for alarin's effects on reproductive and feeding systems. First, we injected male mice ICV with full-length alarin (Ala1-25) or peptide fragments missing residues at the amino-terminal end (Ala3-25 or Ala6-25 Cys). Neither peptide fragment alone, significantly increased food intake in male mice compared to controls. Second, ICV injection of Ala1-25, but not Ala3-25, significantly (p < 0.01) increased GnRH-mediated LH secretion. Surprisingly, Ala6-25 Cys significantly (p < 0.05) inhibited plasma LH secretion and inhibited Ala1-25 actions. In conclusion, elimination of the first five amino acids of alarin not only abolishes the biological activity of alarin, but becomes an antagonist to alarin-specific effects. Furthermore, Ala6-25 Cys seems to act as a specific antagonist to putative alarin receptors and therefore may be an important tool in identifying alarin-specific receptors.
(Copyright © 2012. Published by Elsevier Ltd.)
Databáze: MEDLINE
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