Melatonin, the neurohormone mainly synthesized in and secreted from the pineal gland of vertebrates following a circadian rhythm, is an important factor regulating various physiological processes, including reproduction. Recent data indicate that melatonin is also synthesized in the ovary and that it acts directly at the level of the ovary to modulate ovarian physiology. In some teleosts, melatonin is reported to affect ovarian steroidogenesis. The direct action of melatonin on the ovary could be a possible factor promoting oocyte maturation in teleosts. A role for melatonin in follicle rupture during ovulation in the teleost medaka has recently emerged. In addition, melatonin is suggested to affect oocyte maturation by its antioxidant activity. However, the molecular mechanisms underlying these direct effects of melatonin are largely unknown.

褪黑激素是一种主要在脊椎动物松果体中合成并分泌的神经激素，它遵循昼夜节律，是调节包括繁殖在内的各种生理过程的重要因素。最近的数据表明，褪黑激素也在卵巢中合成，它直接作用于卵巢水平以调节卵巢生理机能。在一些硬骨鱼中，据报道褪黑激素会影响卵巢类固醇生成。褪黑激素对卵巢的直接作用可能是促进硬骨鱼卵母细胞成熟的一个可能因素。最近出现了褪黑激素在硬骨鳉排卵期间卵泡破裂中的作用。此外，建议褪黑激素通过其抗氧化活性影响卵母细胞成熟。然而，褪黑激素的这些直接作用背后的分子机制在很大程度上是未知的。