Hayes F J, Crowley W F
Massachusetts General Hospital and Harvard Medical School, Boston 02114, USA.
Horm Res. 1998;49(3-4):163-8. doi: 10.1159/000023165.
Initiation and maintenance of the reproductive axis in the human is contingent upon the pulsatile secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. In man, tracking endogenous GnRH secretion relies on frequent peripheral sampling of three glycoprotein products of the gonadotrope, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and free alpha-subunit (FAS). FAS is superior to LH as a surrogate marker of GnRH secretory dynamics in those circumstances where GnRH secretion is rapid or where the pituitary LH response is low. The pattern of GnRH secretion is constantly changing across development; from high levels during the neonatal period, through a period of quiescence in mid-childhood, followed by sleep-entrained reactivation of the reproductive axis at the onset of puberty, ultimately culminating in the adult pattern of pulsatile secretion which in the male is approximately every 2 h and in the female varies with the stage of the menstrual cycle. This episodic mode of secretion allows differential impact of feedback mechanisms on the GnRH neurons and facilitates the maintenance of the reproductive axis during periods of stress by allowing frequency and amplitude modulations.
人类生殖轴的启动和维持取决于下丘脑促性腺激素释放激素（GnRH）的脉冲式分泌。在人类中，追踪内源性GnRH分泌依赖于对促性腺激素细胞的三种糖蛋白产物——黄体生成素（LH）、卵泡刺激素（FSH）和游离α亚基（FAS）进行频繁的外周血采样。在GnRH分泌迅速或垂体LH反应较低的情况下，FAS作为GnRH分泌动态的替代标志物优于LH。GnRH的分泌模式在整个发育过程中不断变化；从新生儿期的高水平，到儿童中期的静止期，随后在青春期开始时睡眠诱导生殖轴重新激活，最终形成成人的脉冲式分泌模式，男性约每2小时一次，女性则随月经周期阶段而变化。这种间歇性分泌模式允许反馈机制对GnRH神经元产生不同影响，并通过频率和幅度调制促进应激期间生殖轴的维持。
