We all know the expression “having an adrenaline rush”. This is in fact what happens in the body when we are faced with sudden danger. At this time, our body prepares the muscles to fight or to flee by increasing the heart rate, the respiratory rate, the blood pressure, the level of sugar in the blood, but also the body temperature.
This reaction of the body to a dangerous situation has long been known to be controlled by direct impulses from the brain, as well as by hormones secreted by the adrenal glands. However, a new study has just shown that the bones also produce a special hormone which participates in the preparation of this response to danger. This is osteocalcin and its role would be to help coordinate the response in question.
It was a team of researchers led by Gerard Karsenty of Columbia University who made this discovery. The article was published in the journal Cell Metabolism.
Bones in action
During their research, the scientists found that blood levels of osteocalcin rise rapidly in humans when they have to speak in public and are under high stress. This same phenomenon occurs in rats and mice when they are shackled or receive electric shocks in the feet, or when they are exposed to the smell of fox urine.
By doing additional experiments on mice, the researchers also found that increasing osteocalcin levels suppresses the body's resting and digestive functions. This allows the activation of defense or flight mechanisms.
According to the information, the results obtained during this study are in addition to the results that the same team had obtained during previous work. These have shown that the bones secrete osteocalcin to help the muscles consume fuel during exercise. They also found that when this hormone was injected into the muscles of slightly older mice, those muscles regained their youth.
See the bones differently
Regarding these results, Karsenty said that the role of bones, which were thought to be only inert structures, should be reviewed. According to him, it is possible that the bones have evolved to be able to protect us from serious dangers by activating the defense or flight response, but also by optimizing muscle functions, and by providing the conditions for our bodies to move and be healthy. escape.
For his part, Robin McAllen of the University of Melbourne indicates that until now, it is not yet known why the body has several means to activate the defense or flight response. Maybe it's to have a backup system if one of the systems breaks down. To reinforce this idea, McAllen stated that people with failing adrenal glands and mice without those glands could still exhibit this defense or flight response.