A team of scientists has stumbled upon an extraordinary finding: a molecule in python blood called para-tyramine-O-sulfate, or pTOS, skyrockets more than 1,000-fold after the snake eats — and it’s got some unexpected effects on appetite and weight loss in mice.
The research, led by Leslie Leinwand of the University of Colorado Boulder and Jonathon Long of Stanford University, involved studying ball and Burmese pythons, which are known for their extreme metabolic swings. After feeding the snakes a meal weighing 25% of their body weight (following a 28-day fast), the team identified over 200 molecules that surged in the blood, but pTOS stood out for its massive increase. This metabolite is produced by the python’s gut bacteria as they break down the amino acid tyrosine, adding a sulfate group and releasing carbon dioxide.
From Python Blood to Appetite Control in Mice
While pTOS isn’t commonly found in lab animals like mice or rats, it does appear in trace amounts in humans — particularly in urine — and may increase after a meal. So, what happens if you give it to mice? The results were striking: both obese and lean male mice given high doses of pTOS, whether by injection or oral dosing, ate significantly less food. In obese mice, food intake dropped enough that they lost 9% of their body weight after four weeks, all without the gastrointestinal upset, muscle loss, or energy drops that often plague current weight-loss medications.
The mechanism appears to involve the ventromedial hypothalamus, a key brain region controlling hunger and satiety. In both mice and pythons, pTOS activated neurons in this area, effectively flipping the “I’m full” switch in the brain.
A New Inspiration for Obesity Drugs?
The discovery is especially intriguing given the recent popularity and side effects of GLP-1 drugs like Ozempic and Wegovy. These medications, initially inspired by a molecule from the Gila monster, have helped millions lose weight but often cause nausea, muscle loss, and other issues. In contrast, pTOS seems to curb appetite without those downsides, at least in mice.
Researchers caution that it’s still early days — there’s much we don’t know about how pTOS works in humans, and its safety and efficacy remain untested. But as Dr. Long puts it, “Maybe by studying these animals, we can identify molecules or metabolic pathways that also affect human metabolism.” Pythons, it seems, could inspire the next generation of weight-loss treatments by revealing nature’s own extreme metabolic solutions.
