Mechanisms of specific regulation of gonadotropn subunits expression by pulsatile GnRH stimulation

PACAP及其受体不仅在中枢神经系统中表达，而且在外周器官中表达，并且作为下丘脑-垂体释放因子以及垂体内的自分泌-旁分泌因子发挥刺激垂体激素合成和释放的功能。 PACAP刺激促性腺激素分泌垂体细胞中促性腺激素α、LH β和FSH β亚单位以及GnRH受体及其自身的PACAP I型受体（PAC 1 R）的表达。反过来，已知作为促性腺激素分泌的关键组分的GnRH刺激促性腺激素细胞中PACAP和PAC 1 R的表达。此外，PAC 1 R存在于产生GnRH的神经元细胞中，PACAP调节GnRH神经元的功能。PACAP通过调节GnRH的释放直接或间接调节促性腺激素，从而发挥生殖功能。

PACAP and its receptor are expressed not only in the central nervous system, but also in peripheral organs and function to stimulate pituitary hormone synthesis and release as both hypothalamic-pituitary releasing factor as well as an autocrine-paracrine factor within the pituitary. PACAP stimulates the expression of the gonadotropin alpha, LH betand FSH beta subunits as well as the GnRH receptor and its own PACAP type I receptor (PAC1R) in gonadotropin-secreting pituitary cells. In turn, GnRH, which has been known as a crucial component of gonadotropin secretion, stimulates the expression of PACAP and PAC1R in gonadotrophs. In addition, PAC1R presents in GnRH-producing neuronal cells and PACAP modulates the functions of GnRH neurons. It is evident that PACAP plays a role in reproductive function through regulating gonadotropins directly or indirectly by modulating GnRH release.