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Simultaneous Effect of Kisspeptin and Galanin on Serum Luteinizing Hormone and Testosterone Levels in Male Rats

Maliheh Talebolhosseini, Homayoun Khazali

Background: Galanin is a neuropeptide with a wide range of physiological functions that also has stimulatory effects on the reproductive axis. Kisspeptin is a crucial neuropeptide for the stimulation of the reproductive function. In the present study, the interaction of kisspeptin and the galanin signaling system was investigated on the mean serum luteinizing hormone (LH) and the testosterone concentrations in rats. Materials and Methods: Fifty-five male Wistar rats in 11 groups (n=5 per group) received saline, kisspeptin (1nmol), P234(1nmol), galanin(1nmol), galantide (1nmol) or simultaneous injections of them via third cerebral ventricle at 07:00 - 07:30. Blood samples were collected at 30 min following the injections. Hormone concentrations were measured using rat kit and the method of the radio-immunoassay (RIA). Results: Kisspeptin or galanin injection significantly increased both the mean serum LH and the testosterone concentration compared to saline (P<0.05). The co-administration of kisspeptin/galanin increased the mean serum LH and the testosterone concentration significantly compared to galanin or saline (P<0.05). The co-administration of kisspeptin/galanin decreased the mean serum LH concentration compared to kisspeptin, this reduction, however, was not statistically significant. Also, testosterone concentration declined in the kisspeptin/galanin group compared to kisspeptin group. Galantide or p234 injection decreases the mean serum LH and the testosterone concentration compared to galanin and kisspeptin, respectively. The co-administration of galantide/p234 lowers the mean serum LH concentration compared to saline. Conclusion: The interaction of hypothalamic galanin and kisspeptin signaling pathways may play an important role in the modulation of hormonal control of the hypothalamus-pituitary-gonadal axis. [GMJ. 2017;6(1):23-29]

Kisspeptin; Galanin; Galantide; Luteinizing Hormone; Testosterone

Crown A, Clifton DK, Steiner RA. Neuropeptide signaling in the integration of metabolism and reproduction. Neuroendocrinology. 2007;86(3):175-82.

Fang P, He B, Shi M, Kong G, Dong X, Zhu Y, et al. The regulative effect of galanin family members on link of energy metabolism and reproduction. Peptides. 2015;71:240-9.

Landry M, Roche D, Angelova E, Calas A. Expression of galanin in the hypothalamic magnocellular neurons of lactating rats: co-existence with vasopressin and oxytocin. J Endocrinol. 1997;155(3):467-81.

Merchentaler I. Galanin and the neuroendocrine axes. EXS. 2010;102:71-85.

Kallo I, Vida B, Deli L, Molna CS, Hrabovszky E, Caraty A, et al. Co-Localisation of Kisspeptin with Galanin or Neurokinin B in Afferents to Mouse GnRH Neurones. J Neuroendocrinol. 2012;24(3):464-76.

Messager S, Chatzidaki EE, Ma D, Hendrick AG, Zahn D, Dixon J, et al. Kisspeptin directly stimulates gonadotropin-releasing hormone release via G protein-coupled receptor 54. Proc Natl Acad Sci U S A. 2005;102(5):1761-6.

Colledge WH. GPR54 and puberty. Trends Endocrinol Metab. 2004;15(9):448-53.

Han SK, Gottsch ML, Lee KJ, Popa SM, Smith JT, Jakawich SK, et al. Activation of gonadotropin-releasing hormone neurons by kisspeptin as a neuroendocrine switch for the onset of puberty. J Neurosci. 2005;25(49):11349-56.

d'Anglemont de Tassigny X, Fagg LA, Dixon JP, Day K, Leitch HG, Hendrick AG, et al. Hypogonadotropic hypogonadism in mice lacking a functional Kiss1 gene. Proc Natl Acad Sci U S A. 2007 Jun 19;104(25):10714-9.

Herbison AE, de Tassigny Xd, Doran J, Colledge WH. Distribution and postnatal development of Gpr54 gene expression in mouse brain and gonadotropin-releasing hormone neurons. Endocrinology. 2010;151(1):312-21.

Thompson EL, Patterson M, Murphy KG, Smith KL, Dhillo WS, Todd JF, et al. Central and peripheral administration of kisspeptin-10 stimulates the hypothalamic-pituitary-gonadal axis. J Neuroendocrinol. 2004;16(10):850-58.

Paxinos G, Watson C. The rat brain in stereotaxic coordinates. 5th ed. San Diego: Academic Press; 2005.

Dube MG, Horvath TL, Leranth C, Kalra PS, Kalra SP. Naloxone reduces the feeding evoked by intracerebroventricular galanin injection. Physiol Behav. 1994;56(4):811-13.

Pandit MA, Saxena RN. Galanin regulation of LH release in male rats. Indian J Exp Biol. 2010;48(6):544-48.

Mahmoudi F, Khazali H, Janahmadi M. Interactions of morphine and Peptide 234 on mean plasma testosterone concentration. Int J Endocrinol Metab. 2014;12(1):e12554.

Branchek TA, Smith KE, Gerald C, Walker MW. Galanin receptor subtypes. Trends Pharmacol Sci. 2000;21(3):109-17.

Whitelaw CM, Robinson JE, Hastie PM, Padmanabhan V, Evans NP. Effects of cycle stage on regionalised galanin, galanin receptors 1-3, GNRH and GNRH receptor mRNA expression in the ovine hypothalamus. J Endocrinol 2012;212(3):353-61.

Lang R, Gundlach AL, Kofler B. The galanin peptide family: Receptor pharmacology, pleiotropic biological actions, and implications in health and disease. Pharmacol Ther. 2007;115(2):177-207.

Rajendren G, Li X. Galanin synaptic input to gonadotropin-releasing hormone perikarya in juvenile and adult female mice: implications for sexual maturity. Brain Res Dev Brain Res. 2001;131(1-2):161-65.

Pielecka-Fortuna J, Chu Z, Moenter SM. Kisspeptin acts directly and indirectly to increase gonadotropin-releasing hormone neuron activity and its effects are modulated by estradiol. Endocrinology. 2008;149(4):1979 -986.

Clarksona J, Hanb SK, Liua X, Leea K, Herbisona AE. Neurobiological mechanisms underlying kisspeptin activation of gonadotropin-releasing hormone (GnRH) neurons at puberty. Mol Cell Endocrinol. 2010;324(1-2):45-50.

Patterson M, Murphy KG, Thompson EL, Patel S, Ghatei MA, Bloom SR. Administration of kisspeptin-54 into discrete regions of the hypothalamus potently increases plasma luteinising hormone and testosterone in male adult rats. J Neuroendocrinol. 2006;18(5):349-54.

Clarkson J, Herbison AE. Postnatal development of kisspeptin neurons in mouse hypothalamus; sexual dimorphism and projections to gonadotropin-releasing hormone neurons. Endocrinology. 2006;147(12):5817-25.

Clarkson J, Herbison AE. Dual Phenotype Kisspeptin-dopamine neurones of the rostral periventricular area of the third ventricle project to gonadotrophin-releasing hormone neurones. J Neuroendocrinol 2011;23(4):293-301.

Porteous R, Petersen SL, Yeo SH, Bhattarai JP, Ciofi P, de Tassigny XD, et al. Kisspeptin neurons co-express met-enkephalin and galanin in the rostral periventricular region of the female mouse hypothalamus. J Comp Neurol. 2011;519(17):3456-69.

Yeo SH. Neuronal circuits in the hypothalamus controlling gonadotrophin-releasing hormone release: the neuroanatomical projections of kisspeptin neurons. Exp Physiol. 2013;98(11):1544-9.

Yun S, Kim DK, Furlong M, Hwang JI, Vaudry H, Seong JY. Does Kisspeptin Belong to the Proposed RF-Amide Peptide Family?. Front Endocrinol (Lausanne). 2014;5:134.

Constantin S, Wray S. Galanin activates G-protein gated inwardly rectifying potassium channels and suppresses kisspeptin-10 activation of GnRH neurons. Endocrinology. 2016;157(8):3197-212.

Smith KE, Walker MW, Artymyshyn R, Bard J, Borowsky B, Tamm JA, et al. Cloned human and rat galanin GALR3 receptors. Pharmacology and activation of G-protein inwardly rectifying K+ channels. J Biol Chem. 1998; 273(36):23321-6.

Wang S, Hashemi T, Fried S, Clemmons AL, Hawes BE. Differential intracellular signaling of the GalR1 and GalR2 galanin receptor subtypes. Biochemistry. 1998;37(19):6711-7.

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