Neill Jimmy D, Musgrove Lois C, Duck L Wayne
University of Alabama School of Medicine, Department of Physiology and Biophysics, MCLM 816, 1918 University Boulevard, Birmingham, AL 35294-0005, USA.
Trends Endocrinol Metab. 2004 Oct;15(8):383-92. doi: 10.1016/j.tem.2004.08.005.
Hypothalamic gonadotropin releasing hormone (GnRH I) and its pituitary receptor are responsible for the CNS regulation of reproduction. However, a second GnRH (GnRH II) is also expressed in humans and a gene that resembles the GnRH II receptor in fish has been identified in humans and monkeys. The amino-acid sequence of this newly identified, seven-transmembrane, G-protein-coupled receptor in monkeys differs from the human GnRH I receptor by having a C-terminal, cytoplasmic tail. GnRH II is approximately 400-fold more potent at GnRH II receptors than GnRH I receptors. GnRH I directly inhibits proliferation of human tumor cells, and GnRH II and its receptor might have a similar role. Limited progress has been made, however, because of difficulty translating the mRNA that encodes the human GnRH II receptor. Nevertheless, such receptors are likely to exist in humans because GnRH II is more inhibitory to tumor cell replication than GnRH I, and GnRH I and GnRH II have reciprocal effects on human decidual stromal cells in culture. The focus of this review is the identity of a possible translatable, functional GnRH II receptor in humans. The two possibilities considered are either that GnRH II receptor mRNA is expressed that encodes either 5 or 7 transmembrane domains or that a GnRH II-responsive complex is formed by the GnRH I receptor and fragments derived from the GnRH II receptor.
下丘脑促性腺激素释放激素（GnRH I）及其垂体受体负责中枢神经系统对生殖的调节。然而，第二种GnRH（GnRH II）也在人类中表达，并且在人类和猴子中已鉴定出一种在鱼类中类似于GnRH II受体的基因。这种新鉴定的、七跨膜、G蛋白偶联受体在猴子中的氨基酸序列与人类GnRH I受体不同，其具有一个C末端胞质尾巴。GnRH II对GnRH II受体的作用效力比对GnRH I受体高约400倍。GnRH I直接抑制人类肿瘤细胞的增殖，并且GnRH II及其受体可能具有类似作用。然而，由于难以翻译编码人类GnRH II受体的mRNA，进展有限。尽管如此，此类受体很可能在人类中存在，因为GnRH II比GnRH I对肿瘤细胞复制的抑制作用更强，并且GnRH I和GnRH II对培养中的人蜕膜基质细胞有相互作用。本综述的重点是人类中一种可能可翻译的功能性GnRH II受体的身份。所考虑的两种可能性是，要么表达编码5个或7个跨膜结构域的GnRH II受体mRNA，要么由GnRH I受体和源自GnRH II受体的片段形成一种GnRH II反应复合物。
