Plate Nº 48 · recorded October 10, 2026
Neuroscience & MindReported finding
Bullfrog Brains Produce Their Own Emergency Fuel, Study Finds
Bullfrog brains can make ketone bodies locally when glucose runs low, University of Missouri researchers report in PNAS — a backup fuel system most animals lack.
By James Calloway3 min read552 words
In brief
- University of Missouri researchers found bullfrog brains can produce ketone bodies locally when glucose is scarce.
- The study was published in the Proceedings of the National Academy of Sciences in 2026 (DOI: 10.1073/pnas.2613981123).
- Lead author Joseph Santin likened the finding to discovering a backup generator in a building assumed to have one power source.
- The backup system may help bullfrogs reactivate brain circuits quickly after winter's hibernation-like state.
- The research may inform study of energy-metabolism disorders including Alzheimer's, ALS and schizophrenia.
Bullfrog brains can manufacture their own backup fuel, defying a decades-old assumption that nearly all animals power their brains with glucose delivered from elsewhere in the body. Researchers at the University of Missouri's College of Arts and Science found that when glucose grows scarce, bullfrog brains switch to producing ketone bodies on the spot, keeping critical neural functions running. The findings appear in the Proceedings of the National Academy of Sciences.
What did the team discover?
Ketone bodies are small energy molecules. In most animals, the liver makes them by breaking down fatty acids when glucose levels drop — during fasting, starvation, or prolonged exercise. Those molecules then travel through the bloodstream to organs, including the brain, which burns them as fuel.
The Mizzou team, led by associate professor of biological sciences Joseph Santin, found that bullfrogs can skip that delivery step entirely. Their brains generate ketones locally, creating an emergency energy reserve exactly where it is needed most.
"Scientists generally believe ketones are delivered to the brain from elsewhere in the body," Santin said. "That's what makes this discovery so exciting. It's like finding a backup generator inside a building that everyone assumed had only one power source."
How does this help bullfrogs survive winter?
The finding helps explain how bullfrogs endure one of the hardest stretches of their year. Each winter they enter a hibernation-like state that slows their metabolism and drains their energy reserves.
By spring, when oxygen and energy stores run low, the animals must rapidly reactivate the brain circuits that control bodily functions. The newly described metabolic backup system may be one reason they manage that transition so quickly and successfully.
The study builds on years of work in Santin's lab examining how frogs withstand conditions that would severely damage or kill most animals. Earlier research showed that the hibernation-like state protects neural circuits during extreme oxygen deprivation. The new results add another layer to that survival strategy: the ability to keep brain activity going when glucose metabolism falters.
What remains unknown?
Several questions are still open. Researchers do not know exactly what triggers the switch to ketone production, or how long bullfrogs can sustain it.
The team does not believe the metabolic shift is permanent. It appears instead to work as a robust backup system that engages when the brain's usual energy supply falls short. Whether other animals share this capacity remains unaddressed in the study.
The results come from a single study in one amphibian species, so the findings should be treated as preliminary until other labs replicate them.
Could this matter for human medicine?
Santin thinks the discovery may eventually help scientists understand the human brain, because bullfrogs and humans share many of the same fundamental biological processes.
By revealing how brains adapt when energy supplies dwindle, the research could open new avenues for studying neurological disorders linked to impaired energy metabolism. The study names Alzheimer's disease, ALS, and schizophrenia as conditions where such insight might apply. Any clinical relevance, however, remains speculative for now.
The paper, authored by Hafsa Yaseen and colleagues and titled "Transforming neural activity to operate without glucose metabolism using brain-derived ketone bodies," was published in the Proceedings of the National Academy of Sciences in 2026 (DOI: 10.1073/pnas.2613981123).
via Phys.org Biology (Source)
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Staff writer covering marketplaces and e-commerce at SciBeat.
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