Bold claim: tiny blood particles may be the hidden highway that ferries certain hormones around your body, and exercise might turn up the traffic. Researchers at Touro University Nevada have identified extracellular vesicles (EVs) as key players in how a set of hormones travels through the body. The study, published in Proceedings of the National Academy of Sciences (PNAS), suggests that physical activity can energize or alter this transport system, with potential implications for energy balance, mood, immune function, brain access, and even how some drugs circulate.
EVs are minuscule particles found in blood and other body fluids, existing outside cells. They shuttle signals between cells within tissues and across organ systems by delivering cargos—proteins, lipids, and nucleic acids—and they also help remove cellular waste. While we already know EVs participate in immune responses and cancer progression, their interactions with hormones are less understood.
The researchers centered their attention on proopiomelanocortin (POMC), a precursor that can be processed into several hormones, including endorphins (the source of the classic runner’s high) and adrenocorticotropic hormone (ACTH), a regulator of the stress response. Since exercise has long been linked to these hormonal changes, the team used physical activity as a way to probe how POMC and EVs might work together.
A striking finding was that intense exercise quadruples the amount of POMC bound to EVs. According to the study’s lead author, Mark Santos, Ph.D., an assistant professor at Touro, this reveals a mechanism beyond a simple “exercise effect.” In his words, exercise-induced stress appears to drive EVs to temporarily function as hormone transport shuttles in the bloodstream.
In laboratory experiments, EV-bound POMC could cross human blood vessel barriers—including the blood-brain barrier—more efficiently than POMC carried alone. Because POMC needs to be converted into mature hormones to trigger responses in the brain, the authors caution that more research is needed to determine how the exercise-triggered rise in POMC influences brain activity.
Aurelio Lorico, MD, PhD, a pathology professor at Touro and co-senior author, highlights the study’s broad potential. He notes that if EVs can carry POMC, the findings could have wide-ranging implications for pain management, metabolism and obesity, inflammation, and the body’s stress response.
Source:
Journal: Hightower, Cheryl E. et al., Physical exercise increases binding of POMC to blood extracellular vesicles, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2525044122
