The next time a tense situation jolts you into fight-or-flight mode, you might want to thank your skeleton for that survival impulse.
Scientists have long pointed to adrenaline as the trigger behind the acute stress response. But recent research at Columbia University suggests that the fight-or-flight mode couldn’t happen without osteocalcin, a bone-derived hormone.
“In bony vertebrates, the acute stress fact is not possible without osteocalcin,” says lead study investigator Gérard Karsenty, MD, PhD. “It entirely changes how we think about how acute stress responses occur.”
Karsenty and the team tracked osteocalcin spikes in lab mice and human study participants during stressful scenarios and found that the hormone boosted heart rate, body temperature, and blood-glucose levels — all signs of the acute stress response. Mice that were genetically engineered to produce no osteocalcin displayed little or no reaction in the same situations.
This makes sense when you consider the protective qualities in our skeletal system, Karsenty notes. “If you think of bone as something which evolved to protect the organism from danger — even the bones in the ear alert us to approaching danger — the hormonal functions of osteocalcin start to make sense.”
So what is adrenaline’s role within the acute stress response? Scientists are no longer sure. Further research is needed — and Karsenty says it may reveal other surprising interorgan signals.