Molecule in python blood could pave way for new obesity drugs, scientists say | Science
Pythons eat the ultimate diet, swallowing an antelope in one go, then going months without eating. Scientists have now identified a molecule that appears to be crucial to this metabolic feat and which they believe could pave the way for a new class of anti-obesity drugs.
When the metabolite python, which increases in their blood after eating, was given to obese mice, they avoided the food and quickly lost weight. Scientists said the molecule could have a similar effect to drugs such as Wegovy.
“Clearly, we’re not snakes,” said Dr. Jonathan Long, an associate professor of pathology at Stanford University and co-author of the research. “But perhaps by studying these animals we can identify molecules or metabolic pathways that also affect human metabolism.”
Burmese pythons can measure more than 5 meters (16 feet) in length and weigh nearly 100 kg (220 pounds). In the wild, snakes consume prey up to 100% of their body weight. In the hours following a python’s meal, its heart expands by 25% and its metabolism increases 4,000-fold to help it digest the meal. They can then go 12 to 18 months without eating, apparently with few ill effects.
Initially, scientists aimed to discover the metabolites involved in the sudden growth of pythons’ hearts after feeding. They examined the blood of young Burmese pythons, weighing about 1.5 to 2.5 kg, before and after a meal of about 25% of their body weight. The laboratory snakes were fasted for 28 days before feeding.
Scientists identified more than 200 molecules that increased significantly in the pythons’ blood within hours of eating, and one molecule that increased more than 1,000 times. This molecule, called pTOS, is produced by snake gut bacteria and is also known to be present in low concentrations in human urine. Long said: “We wondered whether this metabolite affected post-feeding physiological changes in the snake. »
However, when pTOS was administered to laboratory mice, no obvious effects on energy expenditure or organ size were observed. “What it regulated was the mice’s appetite and eating behaviors,” Long added.
Obese mice given pTOS ate significantly less than control mice and, after 28 days, had lost 9% of their body weight.
The molecule appears to work in a different way from GLP-1 drugs such as Wegovy, which work in part by slowing stomach emptying, making people feel full longer, but is also linked to nausea, constipation and stomach pain. Instead, pTOS appears to act on a region of the brain, the hypothalamus, known to regulate appetite.
Professor Leslie Leinwand, a biologist at the University of Colorado Boulder who has studied pythons for two decades and is a co-author of the research, said: “We have essentially discovered an appetite suppressant that works in mice without some of the side effects of GLP-1 drugs. »
Leinwand said more research would be needed before the findings could be applied clinically, but that since pTOS occurs naturally in humans, it should be safe. “I have a healthy respect for snakes,” Leinwand added. “We can learn so much from these animals that have evolved to do extreme things. »
The results are published in the journal Nature Metabolism.
