Based on extensive studies on gonadotropin-releasing hormone (GnRH) it was assumed that GnRH is the only hypothalamic neurohormone regulating gonadotropin release in vertebrates. In 2000, however, Tsutsui's group discovered gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that inhibits gonadotropin release, in quail. Subsequent studies by Tsutsui's group demonstrated that GnIH is conserved among vertebrates, acting as a new key neurohormone regulating reproduction. GnIH inhibits gonadotropin synthesis and release through actions on gonadotropes and GnRH neurons via GnIH receptor, GPR147. Thus, GnRH is not the sole hypothalamic neurohormone controlling vertebrate reproduction. The following studies by Tsutsui's group have further demonstrated that GnIH has several important functions in addition to the control of reproduction. Accordingly, GnIH has drastically changed our understanding about reproductive neuroendocrinology. This review summarizes the discovery of GnIH, progress in GnIH research on reproductive physiology and behavior and perspective of GnIH research on neuroendocrine regulation of reproduction.

基于对促性腺激素释放激素（GnRH）的广泛研究，我们认为GnRH是调节脊椎动物促性腺激素释放的唯一下丘脑神经激素。然而，在2000年，Tstsuui的小组在鹌鹑中发现了促性腺激素抑制激素（GnIH），一种抑制丘脑中促性腺激素释放的新型下丘脑神经肽。Tsutsui小组的后续研究表明，GnIH在脊椎动物中是保守的，是调节生殖的新的关键神经激素。GnIH通过GnIH受体GPR147对促性腺激素和GnRH神经元的作用来抑制促性腺激素的合成和释放。因此，GnRH不是控制脊椎动物繁殖的唯一下丘脑神经激素。Tsutsui'的以下研究 小组进一步证明，GnIH除了控制繁殖外，还具有其他重要功能。因此，GnIH彻底改变了我们对生殖神经内分泌学的理解。本文综述了GnIH的发现，GnIH在生殖生理和行为研究方面的进展以及GnIH在神经内分泌调控生殖方面的研究前景。