Circadian rhythmicity is the ability of most organisms to adapt to the environment and play a major role in orchestrating daily physiology. Carbohydrate and lipid metabolism in the liver has been reported to follow a certain circadian rhythm. Uridine, a uracil nucleoside, has a role in nutrient availability, adipocyte function, and cellular energy homeostasis. Uridine supplementation also affected glucose and lipid homeostasis in previous studies. 

Researchers from the Institute of Subtropical Agriculture (ISA) of the Chinese Academy of Sciences conducted a 2 weeks experiment to determine the effects of HFD and concomitant uridine supplementation at different times throughout the day on liver lipid and glucose metabolism in C57BL/6J mice. 

This study showed that uridine supplementation, independent of the time of administration during the day, significantly reduced body weight gain (P<0.05). Furthermore, liver weight and ratio showed a strong time dependence (P<0.001). Additionally, oral administration of uridine during daytime or nighttime changed the expression levels of genes involved in the metabolism of uridine (SLC29A1, UMPS, UPP, UGT1A1, and DHODH; P<0.05). Furthermore, uridine affected the levels of 10 fatty acids, lipid and glucose gene (FASN, LCAT, PC, PEPCK, GSK3β, and GLUT2; P<0.05) depending on the timing of administration (P<0.05). In conclusion, oral supplementation with uridine affected the diurnal variations in liver nucleotide and lipid metabolism, which contributed to the weight loss in HFD-fed mice. 

This research was funded by grants from the National Key R&D Program of China (2016YFD0500504, 2016YFD0501201), the STS Program of Chinese Academy of Sciences (KFJ-STSQYZX-031), CAS President’s International Fellowship for Visiting Scientists (2019VBA0015). 

The study, titled “Uridine dynamic administration affects circadian variations in lipid metabolisms in the liver of high fat-diet-fed mice” has been published in Chronobiology International, and details could be found at https://www.tandfonline.com/doi/full/10.1080/07420528.2019.1637347. 

Contact: WU Xin 

E-mail: wuxin@isa.ac.cn 

Institute of Subtropical Agriculture, Chinese Academy of Sciences