Center of Marine Biotechnology, University of Maryland Biotechnology Institute, Baltimore, MD, USA.
Gen Comp Endocrinol. 2010 Feb 1;165(3):438-55. doi: 10.1016/j.ygcen.2009.04.017. Epub 2009 Apr 23.
This review aims at synthesizing the most relevant information regarding the neuroendocrine circuits controlling reproduction, mainly gonadotropin release, in teleost fish. In teleosts, the pituitary receives a more or less direct innervation by neurons sending projections to the vicinity of the pituitary gonadotrophs. Among the neurotransmitters and neuropeptides released by these nerve endings are gonadotrophin-releasing hormones (GnRH) and dopamine, acting as stimulatory and inhibitory factors (in many but not all fish) on the liberation of LH and to a lesser extent that of FSH. The activity of the corresponding neurons depends on a complex interplay between external and internal factors that will ultimately influence the triggering of puberty and sexual maturation. Among these factors are sex steroids and other peripheral hormones and growth factors, but little is known regarding their targets. However, very recently a new actor has entered the field of reproductive physiology. KiSS1, first known as a tumor suppressor called metastin, and its receptor GPR54, are now central to the regulation of GnRH, and consequently LH and FSH secretion in mammals. The KiSS system is notably viewed as instrumental in integrating both environmental cues and metabolic signals and passing this information onto the reproductive axis. In fish, there are two KiSS genes, KiSS1 and KiSS2, expressed in neurons of the preoptic area and mediobasal hypothalamus. Pionneer studies indicate that KiSS and GPR54 expression seem to be activated at puberty. Although precise information as to the physiological effects of KiSS1 in fish, notably on GnRH neurons and gonadotropin release, is still limited, KiSS neurons may emerge as the "gatekeeper" of puberty and reproduction in fish as in mammals.
这篇综述旨在综合有关控制鱼类生殖的神经内分泌回路的最相关信息,主要是促性腺激素释放。在硬骨鱼类中,垂体或多或少地直接接受来自投射到垂体促性腺细胞附近神经元的神经支配。这些神经末梢释放的神经递质和神经肽包括促性腺激素释放激素(GnRH)和多巴胺,它们作为刺激和抑制因子(在许多但不是所有鱼类中),对 LH 的释放以及对 FSH 的释放有一定的影响。相应神经元的活动取决于外部和内部因素的复杂相互作用,这些因素最终会影响青春期和性成熟的触发。这些因素包括性激素和其他外周激素和生长因子,但对于它们的靶标知之甚少。然而,最近一个新的因素进入了生殖生理学领域。KiSS1 最初被称为肿瘤抑制因子称为 metastin,及其受体 GPR54,现在是调节 GnRH 的核心,进而调节哺乳动物的 LH 和 FSH 分泌。KiSS 系统特别被认为是整合环境线索和代谢信号并将这些信息传递给生殖轴的重要因素。在鱼类中,有两个 KiSS 基因,KiSS1 和 KiSS2,表达于前脑区和中脑基底部的神经元中。初步研究表明,KiSS 和 GPR54 的表达似乎在青春期被激活。尽管关于 KiSS1 在鱼类中的生理作用,特别是对 GnRH 神经元和促性腺激素释放的影响的精确信息仍然有限,但 KiSS 神经元可能像在哺乳动物中一样,成为鱼类青春期和生殖的“守门员”。