It is well established that regular exercise it benefits our bodies, particularly in protecting against obesity, but scientists continue to take a closer look at why this happens at the molecular level.
In a new study, scientists put mice through intense treadmill workouts and analyzed how chemicals in the animals’ cells began to change over time. They found the appearance of a metabolite called Lac-Phe (N-lactoyl-phenylalanine), synthesized from lactate and phenylalanine.
Phenylalanine is an amino acid that combines to make protein, and you may be familiar with lactate: it’s produced by the body after strenuous exercise.
The study authors believe they have found an important biological pathway opened by exercise, which then has an impact on the rest of the body, specifically the level of appetite and the amount of food eaten.
Other tests confirmed these results. The researchers administered high doses of Lac-Phe to mice on a high-fat diet, resulting in the mice eating about half as much food over the next 12 hours compared to a group of control mice. Meanwhile, the movement and energy expenditure of the animals remained unchanged.
Over a 10-day period, doses of Lac-Phe led to a decrease in food intake, a resulting decrease in body weight, and improved glucose tolerance in the mice. Those are positive results when you think about ways to combat obesity and obesity-related diseases.
However, there were some caveats. Differences in appetite suppression caused by Lac-Phe were only noted after exercise and in mice on a high-fat diet. The same effects were not seen in more sedentary mice fed normally.
The scientists also looked at the effects of exercise in humans and racehorses, and also found elevated levels of Lac-Phe, especially after running in people. However, side effects were not tested, and more research will be needed to see if these results fully translate to humans.
By shedding more light on molecular responses to physical activity, the study findings will help in several areas of research, including treatments.
There is likely much more to discover. The researchers note that since Lac-Phe is produced in multiple cell types in mice, it’s probably not just the body’s muscles that know when we’re exercising.
“Future work uncovering the downstream molecular and cellular mediators of Lac-Phe action in the brain may provide new therapeutic opportunities to capture the cardiometabolic benefits of physical activity for human health.” researchers write.
The research has been published in Nature.
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