Circadian rhythms and clock gene expressions are regulated by the suprachiasmatic nucleus in the hypothalamus, and melatonin is produced in the pineal gland. Although the brain detects the light through retinas and regulates rhythms and melatonin secretion throughout the body, the liver has independent circadian rhythms and expressions as well as melatonin production. Previous studies indicate the association between circadian rhythms with various liver diseases, and disruption of rhythms or clock gene expression may promote liver steatosis, inflammation, or cancer development. It is well known that melatonin has strong antioxidant effects. Alcohol drinking or excess fatty acid accumulation produces reactive oxygen species and oxidative stress in the liver leading to liver injuries. Melatonin administration protects these oxidative stress-induced liver damage and improves liver conditions. Recent studies have demonstrated that melatonin administration is not limited to antioxidant effects and it has various other effects contributing to the management of liver conditions. Accumulating evidence suggests that restoring circadian rhythms or expressions as well as melatonin supplementation may be promising therapeutic strategies for liver diseases. This review summarizes recent findings for the functional roles and therapeutic potentials of circadian rhythms and melatonin in liver diseases.

中文翻译：

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肝脏疾病中的褪黑激素和昼夜节律：功能作用和潜在疗法。

昼夜节律和时钟基因表达由下丘脑的视交叉上核调节，而褪黑激素在松果体中产生。虽然大脑通过视网膜检测光线并调节全身的节律和褪黑激素的分泌，但肝脏具有独立的昼夜节律和表达以及褪黑激素的产生。先前的研究表明，昼夜节律与各种肝脏疾病之间存在关联，而节律或时钟基因表达的破坏可能会促进肝脏脂肪变性、炎症或癌症的发展。众所周知，褪黑激素具有很强的抗氧化作用。饮酒或过量的脂肪酸积累会在肝脏中产生活性氧和氧化应激，导致肝损伤。褪黑激素给药可保护这些氧化应激引起的肝损伤并改善肝脏状况。最近的研究表明，服用褪黑激素不仅具有抗氧化作用，而且还具有多种其他有助于控制肝脏疾病的作用。越来越多的证据表明，恢复昼夜节律或表达以及补充褪黑激素可能是肝脏疾病的有希望的治疗策略。本综述总结了最近关于昼夜节律和褪黑激素在肝脏疾病中的功能作用和治疗潜力的发现。越来越多的证据表明，恢复昼夜节律或表达以及补充褪黑激素可能是肝脏疾病的有希望的治疗策略。本综述总结了最近关于昼夜节律和褪黑激素在肝脏疾病中的功能作用和治疗潜力的发现。越来越多的证据表明，恢复昼夜节律或表达以及补充褪黑激素可能是肝脏疾病的有希望的治疗策略。本综述总结了最近关于昼夜节律和褪黑激素在肝脏疾病中的功能作用和治疗潜力的发现。