Exercise Supercharges Hormone Transport to the Brain

New research from Touro University Nevada reveals that physical activity enhances the delivery of hormones to the brain. The study pinpoints extracellular vesicles (EVs), tiny particles circulating in the bloodstream, as key transporters of hormone precursors.

Specifically, scientists found that during intense exercise, the amount of the hormone precursor POMC attached to EVs quadrupled. This discovery highlights a previously unknown mechanism by which exercise may influence shifts in stress levels, energy balance, and mood.

The study, published in the journal *Proceedings of the National Academy of Sciences* (PNAS), also demonstrated that POMC bound to EVs crosses blood vessel barriers, including the blood-brain barrier, more efficiently than POMC alone. This finding offers valuable insight into how exercise can affect brain function. The researchers believe these results could lead to a better understanding of metabolism, pain management, mental health, immune responses, and even drug delivery methods.

EVs are abundant in bodily fluids and play a crucial role in cell-to-cell communication by carrying proteins, lipids, and nucleic acids. They also aid in removing cellular waste. While scientists recognize the importance of EVs in processes like immune response and cancer progression, their interaction with hormones has remained largely unexplored.

The research team concentrated on proopiomelanocortin (POMC), a hormone precursor that transforms into hormones like endorphins (associated with the "runner's high") and adrenocorticotropic hormone (ACTH), which regulates the body's response to stress. The scientists used exercise to induce changes and study the interactions between POMC and EVs, given the established link between exercise and these hormones.

According to Mark Santos, Ph.D., assistant professor at Touro University and the study’s first author, the findings reveal a new biological mechanism where the stress induced by exercise causes EVs to temporarily function as hormone transport shuttles in the bloodstream. The study further showed that EV-bound POMC could more effectively cross human blood vessel barriers in the lab, including the blood-brain barrier, compared to POMC alone.

Aurelio Lorico, MD, PhD, professor of pathology at Touro and co-senior author of the study along with Cheryl Hightower, suggests that the discovery that EVs can carry POMC has far-reaching potential implications for pain management, metabolism and obesity, inflammation, and the stress response. Further research is necessary to fully understand how the exercise-induced increase in POMC impacts the brain, particularly since POMC requires processing into mature hormones to trigger a response in the brain.