@sciencefunn: 1st slide: The hormone is called osteocalcin. It’s produced by cells in bone. In studies with mice, when the animals are exposed to acute stress (e.g. predator cues, restraint), osteocalcin levels in their bloodstream increased within a few minutes. Mice that cannot produce osteocalcin, or whose receptors for it are altered, show a much weaker “fight-or-flight” response to stress. Heart rate, glucose levels, body temperature etc. do not rise as much. Similar effects have been seen in humans: people under stress (public speaking etc.) show increases in osteocalcin. We share wholesome science content. Feel free to follow us 👉 @sciencefunn for more.