Title:Melatonin and its Emerging Physiological Role in Reproduction:
A Review and Update
Volume: 24
Issue: 4
Author(s): Ruifeng Shao, Ying Wang, Chihua He and Ligang Chen*
Affiliation:
- Department of Respiratory and Critical Care Medicine, The First People’s
Hospital of Jingzhou, No.55 Jianghan North Road, Jingzhou 434021, Hubei, China
Keywords:
Melatonin, reproduction, hypothalamic-pituitary-gonadal axis, tumor therapy, fertilization rate, neuroendocrine hormone.
Abstract: Melatonin is a neuroendocrine hormone secreted by the pineal gland. The
secretion of melatonin follows a circadian rhythm controlled by the suprachiasmatic
nucleus, and its secretion is synchronized with the changes in light and dark periods in
nature, with the highest secretion level at night. Melatonin is a critical hormone that
coordinates external light stimulation and cellular responses of the body. It transmits
information about the environmental light cycle, including the circadian and seasonal
rhythms, to the relevant tissues and organs in the body, which, along with changes in its
secretion level, ensures that its regulated functional activities are adapted in response to
changes in the outside environment. Melatonin takes beneficial actions mainly through
the interaction with specific membrane-bound receptors, termed MT1 and MT2.
Melatonin also acts as a scavenger of free radicals via non-receptor-mediated
mechanism. For more than half of acentury melatonin has been associated with
vertebrate reproduction, especially in the context of seasonal breeding. Though modern
humans show little remaining reproductive seasonality, the relationships between
melatonin and human reproduction continue to attract extensive attention. Melatonin
plays important roles in improving mitochondrial function, reducing the damage of free
radicals, inducing oocyte maturation, increasing fertilization rate and promoting
embryonic development, which improves the outcomes of in vitro fertilization and
embryo transfer. The present article reviews the progress that has been made in our
evolving understanding of the physiological role of melatonin in reproduction and its
potential clinical applications in reproductive medicine.