Melatonin Receptors: A Key Mediator in Animal Reproduction

SIMPLE SUMMARY: Animal reproduction is closely related to economic benefits and food safety in domestic animals, as well as human fertility. There are many factors that affect the reproductive ability of animals, among which studies have confirmed that melatonin can affect animal reproduction. Melatonin receptors play important roles in mediating melatonin signaling, and they are expected to become a drug target for the improvement of animal reproduction capacity and treatment of reproductive diseases. In this review, we briefly summarize melatonin receptors MT1- and MT2-mediated signal transduction, as well as their role in reproductive regulation, including their effects on gametogenesis, gamete quality, reproductive rhythm, endocrine function, and embryonic development. We also briefly summarize the developments in pharmacological research regarding melatonin receptors as drug targets, which can provide a future perspective for the development of drugs and therapeutic methods based on melatonin receptors or their mediated signaling pathways. ABSTRACT: Melatonin, a hormone produced by the mammalian pineal gland, influences various physiological activities, many of which are related to animal reproduction, including neuroendocrine function, rhythm regulation, seasonal behavior, gonadogenesis, gamete development and maturation, sexual maturation, and thermoregulation. Melatonin exerts beneficial actions mainly via binding with G-protein-coupled receptors (GPCR), termed MT1 and MT2. Melatonin receptors are crucial for mediating animal reproduction. This paper reviews the characteristics of melatonin receptors including MT1 and MT2, as well as their roles in mediating signal transduction and biological effects, with a focus on their function in animal reproduction. In addition, we briefly summarize the developments in pharmacological research regarding melatonin receptors as drug targets. It is expected that this review will provide a reference for further exploration and unveiling of melatonin receptor function in reproductive regulation.