How does the brain signal the liver to begin processing after a period of fasting?
Fasting stimulates autophagy in our body, as a result of which the body turns on the waste disposal system of cells and receives new energy.
Researchers from the Institute of Metabolic Research. Max Planck in Cologne during experiments on mice showed that the brain plays a crucial role in this process.
Even after a short period of fasting, the brain releases corticosterone, and thus autophagy begins in the liver.
So far it has been assumed that the liver cells themselves are responsible for this. In the long term, these results may help us understand why fasting is so beneficial to the body.
Autophagy is essential for survival as it is a natural destruction mechanism that systematically destroys unnecessary (or defective or damaged) cellular components using the cell’s waste disposal system and new energy is generated from this.
This type of body detoxification largely keeps the body fit and youthful.
“Until now, we assumed that the cells in our body would basically sense themselves when they lack energy and then promote autophagy,” explains Wei Chen, a postdoctoral fellow at the Max Planck Institute for Metabolic Research and lead author of the study. But we found in mice that the brain plays a crucial role in this.”
In the experiments, the researchers did not feed the mice for four hours, during which time they usually eat a lot. This is similar to skipping breakfast, however mice consume about 40% of their food at breakfast.
They then studied how the AgRP neurons, a group of 3,000 neurons in the brain’s hunger center, the hypothalamus, responded to this brief fast.
Surprisingly, they found that during fasting, the brain sends not only signals to stimulate the organ system to eat, but also signals to activate autophagy.
The brain communicates with the liver
The researchers were able to determine how the brain interacts with the liver. When energy levels are low, neurons stimulate the release of the hormone corticosterone, which then stimulates autophagy activation in liver cells. They also managed to figure out in detail the exact pathways along which the signal is transmitted to the brain, thus identifying the neurons involved in this process.
They were also able to show that blocking this signal results in a lack of autophagy despite starvation.
The researchers suggest that the brain provides the first initial signal for the rapid start of autophagy. They believe that the liver cells will also start the recycling system themselves, but only at a later stage.
Jens Bruning, leader of the study and director of the Max Planck Institute for Metabolic Research, explains: “Our study shows that autophagy is controlled not only in the body cells themselves, but also in the brain. In the long term, we would like to see if this newly discovered mechanism resides in the brain to “contribute to the beneficial effects of fasting.”
The work was published in the journal Cell Metabolism.
Source: Medical Express
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