Inhibition of Sexual Maturation in Male Rats by Melatonin: Evidence Linking the Mechanism of Action to Changes in the Regulation of Hypothalamic Neuropeptide Y

1992 ◽  
Vol 4 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Roger Corder ◽  
C. Dominique Walker ◽  
Rolf G. Gaillard ◽  
Michel L. Aubert
Keyword(s):  
Neuropeptide Y ◽  
Mechanism Of Action ◽  
Sexual Maturation ◽  
Male Rats

Testosterone Depletion and Its Possible Mechanism of Action by Chronic Administration of Metastin Analogs, KiSS1-305, TAK-448, and TAK-683, in Adult Male Rats

2011 ◽  
pp. P3-148-P3-148
Author(s):  
Hisanori Matsui ◽  
Akira Tanaka ◽  
Kotaro Yokoyama ◽  
Yoshihiro Takatsu ◽  
Kaori Ishikawa ◽  
...  
Keyword(s):  
Mechanism Of Action ◽  
Adult Male ◽  
Chronic Administration ◽  
Male Rats

scholarly journals Advancement of Sexual Maturation in Male Rats by Pituitary Transplants

1979 ◽  
Vol 21 (5) ◽  
pp. 1263-1271 ◽  
Author(s):  
Ronald A. P. de Jong ◽  
Pieter van der Schoot
Keyword(s):  
Sexual Maturation ◽  
Male Rats

scholarly journals Upregulation of Kiss-1 and Gpr54 Genes Expression in Pituitary of Male Rats Following the Central Administration of Neuropeptide Y

2019 ◽  
Vol 4 (4) ◽  
pp. 137-142
Author(s):  
Vahid Azizi ◽  
Shahrbanoo Oryan ◽  
Homayuon Khazali ◽  
Abdolkarim Hosseini
Keyword(s):  
Gene Expression ◽  
Pituitary Gland ◽  
Neuropeptide Y ◽  
Wistar Rats ◽  
Third Ventricle ◽  
Male Rats ◽  
Control Group ◽  
Central Administration ◽  
Reproductive Axis ◽  
Male Wistar Rats

Introduction: The neuropeptide Y (NPY) in the neural circuits of the hypothalamus has a stimulating effect on reproductive activities in mammals. Kisspeptin (KiSS1) is a quintessential neurotransmitter in the reproductive axis which directly stimulates gonadotropin-releasing hormone neurons in the hypothalamus. The distribution of KiSS1 expressing cells in the pituitary was described previously. Despite earlier reports showing the KiSS1 receptor, G-protein coupled receptor 54 (GPR54) expression in the pituitary, the potential physiological roles of kisspeptin at this gland have remained obscure. Accordingly, this study investigated the role of NPY on the relative expression of Kiss1 and Gpr54 genes in the pituitary gland in male Wistar rats. Methods: In general, 20 male Wistar rats weighing 200-250 g in 4 groups (5 in each group) received saline, NPY (2.3 nM), BIBP3226 (NPY receptor antagonist, 7.8 nM), and NPY+ BIBP3226. Then, they received the simultaneous injection of these molecules through the third ventricle of the brain. Finally, the relative mean expressions of Kiss1 and Gpr54 genes in the anterior pituitary were quantitatively analyzed by the real-time polymerase chain reaction. Results: The central injection of NPY increased the relative mean expressions of Kiss1 and Gpr54 genes in the pituitary gland compared to the control group although the injection of BIBP3226 eradicated these effects. However, the gene expression of Gpr54 in the rats receiving NPY coupled with BIBP3226 in hypophysis in comparison to the group receiving only NPY demonstrated a significant reduction (P<0.05). Conclusion: Overall, the central injection of NPY stimulated the gene expression of Kiss1 and Gpr54 in the pituitary gland.

scholarly journals Prenatal undernutrition disrupted the sexual maturation, but not the sexual behavior, in male rats

2017 ◽  
Vol 16 (4) ◽  
pp. 325-329 ◽  
Author(s):  
Toshiya Matsuzaki ◽  
Munkhsaikhan Munkhzaya ◽  
Altankhuu Tungalagsuvd ◽  
Yiliyasi Mayila ◽  
Takeshi Iwasa ◽  
...  
Keyword(s):  
Sexual Behavior ◽  
Sexual Maturation ◽  
Male Rats ◽  
Prenatal Undernutrition

Mechanism of action of Hexarelin. I. Growth hormone-releasing activity in the rat

1996 ◽  
Vol 135 (4) ◽  
pp. 481-488 ◽  
Author(s):  
Antonio Torsello ◽  
Roberta Grilli ◽  
Marina Luoni ◽  
Margherita Guidi ◽  
Maria Cristina Ghigo ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mechanism Of Action ◽  
Direct Action ◽  
Male Rats ◽  
Surgical Ablation ◽  
Adult Rats ◽  
Gh Secretion ◽  
Plasma Gh

Torsello A, Grilli R, Luoni M, Guidi M, Ghigo MC, Wehrenberg WB, Deghenghi R, Müller EE, Locatelli V. Mechanism of action of Hexarelin. I. Growth hormone-releasing activity in the rat. Eur J Endocrinol 1996;135:481–8. ISSN 0804–4643 We have reported Hexarelin (HEXA), an analog of growth hormone-releasing peptide 6 (GHRP-6), potently stimulates growth hormone (GH) secretion in infant and adult rats. This study was undertaken to further investigate Hexarelin's mechanisms of action. In 10-day-old pups, treatments with HEXA (80 μg/kg, b.i.d.) for 3–10 days significantly enhanced, in a time-related fashion, the GH response to an acute HEXA challenge. Qualitatively similar effects were elicited in pups passively immunized against growth hormone-releasing hormone (GHRH) from birth. In adult male rats, a 5-day pretreatment with HEXA (150 μg/kg, b.i.d.) did not enhance the effect of the acute challenge, and the same pattern was present after a 5-day pretreatment in male rats with surgical ablation of the mediobasal hypothalamus (MBH-ablated rats). In addition, in adult sham-operated rats, Hexarelin (300 μg/kg, iv) induced a GH response greater (p < 0.05) than that induced by GHRH (2 μg/kg, iv). However, in MBH-ablated rats 7 days after surgery, GHRH was significantly (p < 0.05) more effective than HEXA, and 30 days after surgery HEXA and GHRH evoked similar rises of plasma GH. Finally, the in vitro Hexarelin (10−6 mol/l) effect was transient while GHRH (10−8 mol/l) induced a longer lasting and greater GH release. Three different mechanisms, not mutually exclusive, are postulated for Hexarelin stimulation of GH secretion in vivo: a direct action on the pituitary, though of minor relevance; an indirect action that involves release of GHRH, of relevance only in adult rats; and an action through the release of a still unknown hypothalamic "factor", which in infant and adult rats elicits GH release acting sinergistically with GHRH. Antonio Torsello, Department of Pharmacology, via Vanvitelli 32, 20129 Milano, Italy

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