Key Laboratory of Animal Genetics and Breeding of the Ministry of Agriculture, Beijing Key Laboratory for Animal Genetic Improvement, College of Animal Science and Technology, China Agricultural University, Beijing, China.
State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, China.
J Pineal Res. 2019 Apr;66(3):e12559. doi: 10.1111/jpi.12559. Epub 2019 Feb 26.
Melatonin is a natural molecule produced in the pineal gland and other tissues. It participates in numerous biological activities including the regulation of reproduction. However, the mechanism by which melatonin affects mammalian female reproductive performance is not fully investigated. In the present study, it was observed that melatonin positively regulated the level of leptin in female mouse and pig. To understand the potential association between melatonin and leptin on the female reproductive activities, the melatonin receptor 1 MT1 knockout (MT1 ) mouse and Leptin knockout (Leptin ) pig were created. It was found that the deficiency of M T1 caused low leptin secretion and litter size in mouse. Meanwhile, the deletion of leptin in pig did not affect melatonin production, but significantly reduced follicle-stimulating hormone, estradiol-17β (E2), and Luteinizing hormone and increased progesterone (P) at estrum stage, which also led to smaller litter size than that in control. Melatonin treatment increased the production of leptin in pigs, while the supplementary of leptin was also able to improve the ovulation number, polar body rates, and expression of StAR in MT1 females. Therefore, it is first time, we described that leptin is the downstream target of melatonin in regulating female reproduction. These findings provide the novel information on the physiology of melatonin in animal reproduction.
褪黑素是松果体和其他组织中产生的一种天然分子。它参与了许多生物活动，包括生殖的调节。然而，褪黑素影响哺乳动物雌性生殖性能的机制尚未完全研究清楚。在本研究中，观察到褪黑素可正向调节雌性小鼠和猪的瘦素水平。为了了解褪黑素和瘦素在雌性生殖活动之间的潜在关联，创建了褪黑素受体 1 MT1 敲除（MT1）小鼠和瘦素敲除（Leptin）猪。结果发现，MT1 的缺乏导致小鼠瘦素分泌和产仔数降低。同时，猪的瘦素缺失并不影响褪黑素的产生，但显著降低了发情期的卵泡刺激素、雌二醇-17β（E2）和黄体生成素，并增加了孕激素（P），这也导致产仔数小于对照组。褪黑素处理增加了猪的瘦素产生，而瘦素的补充也能改善 MT1 雌性动物的排卵数、极体率和 StAR 的表达。因此，这是首次描述瘦素是褪黑素调节雌性生殖的下游靶标。这些发现为动物生殖中褪黑素的生理学提供了新的信息。
