Fat cells were found to help the liver during fasting and for being responsible for the regulation of glucose and uridine during the fasting stage. Uridine is a metabolite used by the body in a series of bioprocesses such as building RNA molecules.
The findings of this study could change the way we treat a number of diseases, among which are diabetes, cancer and neurological disorders. The research was carried out by researchers at the UT Southwestern Medical Center, and its findings were published in the journal Science. The results of this study were replicated in rat, mouse and human studies.
Fat Cells Helpful For Liver During Fasting
Metabolites are important substances which result from a metabolic activity of the body. For instance, the glucose (quantity of sugar in the blood) produced while metabolizing starches or complex sugars is a metabolite.
Similar to glucose, every cell in the human body has to use uridine to function properly. The liver produces uridine for the circulatory system, as many textbooks indicate.
However, this study found that the liver doesn't just produce uridine, but it's the primary producer of this metabolite, only in the fed state. At the same time, the production of uridine is passed on to the fat cells during the fasted state.
According to the study, this new way of understanding the production of uridine in the body is similar to the process of labor division. During fasting, it's the liver that produces glucose, and fat cells help it with the production of uridine for the bloodstream.
While uridine is known to have multiple roles inside the human body, the current research was the first to report fat cells producing plasma uridine while the body is going through the fasting stage. Additionally, the finding is that the energy balance of the body is regulated by a fat cell-liver-uridine axis.
"It turns out that having uridine in your gut helps you absorb glucose; therefore uridine helps in glucose regulation," noted Dr. Philipp Scherer, senior author of the study and Director of UT Southwestern's Touchstone Center for Diabetes Research.
Dr. Yingfeng Deng, the lead author of the research, observed that the levels of uridine in the blood increase during fasting, and drop during feeding. In the feeding process, the liver is responsible for a drop in the levels of uridine, as it secretes it into bile. The uridine is then transported to the gallbladder, and then to the gut, where it plays an important role in absorbing nutrients.
"We clarify the mechanism underlying the rapid reduction of plasma uridine upon refeeding, which involves both reduction of uridine synthesis in adipocytes and enhancement of its clearance through the bile," noted the research.
Uridine Levels And Future Fasting Research
Further research starting from these findings will investigate the effects of reducing feeding-induced uridine levels in organs that use mainly uridine from plasma.
Additionally, whether or not bariatric surgery affects udirine levels as well is another possible research direction. The results of this question could impact the way we treat the severely obese, as this study also underlined that there is a direct connection between temperature regulation and metabolism.
