Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat
Rat RFamide-related peptide-3 stimulates GH secretion, inhibits LH secretion, and has variable effects on sex behavior in the adult male rat
复制标题
DOI：
10.1016/j.yhbeh.2006.09.009
复制
发表时间：
2007-01-01
影响因子：
3.5
通讯作者：
Fraley, Gregory S.
中科院分区：
文献类型：
--
作者：
Johnson, Marlie A.;Tsutsui, Kazuyoshi;Fraley, Gregory S.
促性腺激素抑制激素（GnIH）是近年来发现的一种鸟类神经肽，对几种鸟类的下丘脑-垂体-促性腺激素轴（HPG）具有季节性调节作用。在鸟类中，GnIH的表达在光不应期增加，并对HPG有抑制作用。最近描述的哺乳动物神经肽，RF-酰胺相关肽-3（RFRP-3），可能与这种鸟类神经肽在遗传上相关且功能上相似。本研究的目的是首先观察大鼠RFRP-3是否在雄性大鼠脑中表达，其次确定ICV注射RFRP-3是否会对进食和性行为以及垂体前叶的激素释放产生影响。结果证实了其他研究，即在已知控制HPG和进食及性行为的雄性大鼠大脑区域中可观察到免疫反应性细胞体和纤维。RFRP-3纤维也被观察到靠近GnRH免疫反应细胞体。行为测试表明，高而非低的ICV RFRP-3（分别为500 ng对100 ng）显著（p < 0.05）抑制了男性性行为的所有方面，同时对其行走能力没有任何可观察到的影响。当这些雄性大鼠接受ICV溶剂时，随后表现出性行为。在抑制性行为的同时，与对照相比，ICV RFRP-3显著（p < 0.05）增加食物摄入。ICV RFRP-3也显著降低了促黄体激素的血浆水平，但增加了生长激素，无论一天中的什么时间;然而，RFRP-3在任何时候都没有改变FSH、甲状腺激素或皮质醇的血浆水平。这些结果表明，尽管RFRP-3对LH的影响与在鸟类中观察到的GnIH相似，但在大鼠中，RFRP-3在调节摄食和生长方面具有额外的作用。(c)2006年爱思唯尔公司All rights reserved.
A recently described avian neuropeptide, gonadotropin inhibitory hormone (GnIH), has been shown to have seasonal regulatory effects on the hypothalamic-pituitary-gonadotropin axis (HPG) in several avian species. In the bird, GnIH expression is increased during the photorefractory period and has inhibitory effects on the HPG. A recently described mammalian neuropeptide, RF-amide-related peptide-3 (RFRP-3), may be genetically related and functionally similar to this avian neuropeptide. The purposes of this study were to first see if rat RFRP-3 is expressed in the male rat brain and second to determine if ICV injections of RFRP-3 will have effects on feeding and sex behaviors, as well as hormone release from the anterior pituitary. Results confirm other studies in that immunoreactive cell bodies and fibers are observable in areas of the male rat brain known to control the HPG and feeding and sex behaviors. RFRP-3 fibers are also observed in close proximity to GnRH immunoreactive cell bodies. Behavioral tests indicate that high but not low ICV RFRP-3 (500 vs. 100 ng, respectively) significantly (p < 0.05) suppressed all facets of male sex behavior while not having any observable effects on their ability to ambulate. Sex behavior was later exhibited when those same male rats received the ICV vehicle. While suppressing sex behavior, ICV RFRP-3 significantly (p < 0.05) increased food intake compared to controls. ICV RFRP-3 also significantly reduced plasma levels of luteinizing hormone but increased growth hormone regardless of the time of day; however, at no time did RFRP-3 alter plasma levels of FSH, thyroid hormone, or cortisol. These results indicate that although RFRP-3 has similar effects on LH as observed with GnIH in avian species, in the rat RFRP-3 has additional roles in regulating feeding and growth. (c) 2006 Elsevier Inc. All rights reserved.