Mice living in the high-altitude, oxygen-starved environment of the Andean mountains survive those harsh conditions by fueling their muscles with carbohydrates. The findings, reported online on December 6 in Current Biology, a Cell Press publication, provide the first compelling evidence of a clear difference in energy metabolism between high- and low-altitude native mammals.
"The high-altitude mice we examined in this study are a rare exception to a general exercise fuel use pattern seen in lowland mammals," said Marie-Pierre Schippers of McMaster University. "Studying exceptions to a rule is often the key to uncovering the mechanisms of a physiological process."
The new study conducted with collaborators from the Universidad Peruana Cayetano Heredia in Peru could therefore lead to increased understanding not only of mountain-dwelling mice but also of other mammals, including humans, said Grant McClelland, also of McMaster University.
At an altitude of roughly 4,000 meters, every breath of air contains about 40 percent less oxygen than it would at sea level. Under those conditions, carbohydrates are the logical energy source. That's because carbs can supply 15 percent more energy for the same amount of oxygen in comparison to fats.
In fact, the idea that high-altitude environments should favor carbohydrate metabolism was proposed almost 30 years ago, but it hadn't really been put to the test. In the new study, the researchers used a powerful multispecies approach, using four native species of mice, two from the Peruvian Andes and two found at sea level.
The researchers found that the high-altitude mice do indeed burn more carbohydrates. Their heart muscles show greater oxidative capacity, too, both adaptations that would afford the animals the ability to remain active at altitude more successfully than their lowland relatives could.
Those differences aren't a matter of adjusting to high versus low altitude but are rather due to inherent differences in the mice that have apparently arisen more than once over the course of evolutionary time.
"This is one of 'nature's solutions' to low atmospheric oxygen," McClelland said. "Our study shows that Andean mouse species have independently evolved a metabolic strategy that maximizes energy yield when little oxygen is available. It is possible that a similar strategy has also evolved in other high-altitude mammals, including humans."
Schippers et al.: "Increase in Carbohydrate Utilization in High-Altitude Andean Mice."
Cell Press: http://www.cellpress.com
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
With funding from the Defense Department, scientists have begun work on devices that would use electric pulses to realign a memory process gone awry
On Friday, the Food and Drug Administration released a vital set of numbers about the routine use of antibiotics …
Side order of veg with that mammoth leg? The Neanderthal diet was probably more varied than we think – using vegetables, herbs and different cooking techniques
An exoskeleton that enables movement and provides tactile feedback has helped eight paralysed people regain sensation and move previously paralysed muscles
A female western gray whale set a new record swimming from Russia to Mexico and back, a total of 13,988 miles, in 172 days
Scientists operating a remote-controlled vehicle about 2,000 feet below water get a rare glimpse of a sperm whale. CBSN's Vladimir Duthiers and Elaine Quijano report on the video.
According to the experts, "blinking is like a kitty kiss"
Genetic profiling of cancer cells can help guide treatment, but such profiles can be ambiguous. Results would be more accurate if all labs tested normal cells from each patient, too.
Researchers in Kenya uncover tools dated to 3.3 million years ago, long before the first humans, as we know them, walked the Earth.
Researchers are facing up to methodological flaws that plague functional magnetic resonance imaging, but the interpretative problems might be harder to solve