Vanecek J
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague.
Rev Reprod. 1999 May;4(2):67-72. doi: 10.1530/ror.0.0040067.
Melatonin inhibits GnRH-induced release of LH and FSH from the neonatal, but not the adult, rat anterior pituitary gland. This action of melatonin is mediated by the specific high-affinity membrane-bound receptors that are absent in adult rats. The intracellular mechanism of melatonin action involves a decrease in intracellular calcium [Ca2+]i in the gonadotrophs; melatonin inhibits GnRH-induced Ca2+ release from endoplasmic reticulum as well as Ca2+ influx through voltage-sensitive channels. Melatonin also inhibits GnRH-induced accumulation of cAMP, which may result in the decreased influx of Ca2+, because cAMP, acting through protein kinase A, stimulates Ca2+ influx into the gonadotrophs. This age-dependent effect of melatonin on gonadotrophin release from the pituitary may be involved in the timing of puberty.
褪黑素抑制新生大鼠而非成年大鼠垂体前叶中促性腺激素释放激素（GnRH）诱导的促黄体生成素（LH）和促卵泡生成素（FSH）释放。褪黑素的这一作用由成年大鼠中不存在的特异性高亲和力膜结合受体介导。褪黑素作用的细胞内机制涉及促性腺细胞内细胞钙（[Ca2+]i）水平降低；褪黑素抑制GnRH诱导的内质网钙释放以及通过电压敏感通道的钙内流。褪黑素还抑制GnRH诱导的环磷酸腺苷（cAMP）积累，这可能导致钙内流减少，因为cAMP通过蛋白激酶A起作用，刺激钙流入促性腺细胞。褪黑素对垂体促性腺激素释放的这种年龄依赖性作用可能与青春期的时间有关。
