At high altitude, carbs are the fuel of choice

Dec 06, 2012
This is a photo of an Andean mouse. Credit: Schippers et al., Current Biology

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 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 of mice, two from the 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."

Explore further: Deep sea fish eyesight similar to human vision

More information: Schippers et al.: "Increase in Carbohydrate Utilization in High-Altitude Andean Mice." DOI: 10.1016/j.cub.2012.10.043

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

Dogs hear our words and how we say them

Nov 26, 2014

When people hear another person talking to them, they respond not only to what is being said—those consonants and vowels strung together into words and sentences—but also to other features of that speech—the ...

Amazonian shrimps: An underwater world still unknown

Nov 26, 2014

A study reveals how little we know about the Amazonian diversity. Aiming to resolve a scientific debate about the validity of two species of freshwater shrimp described in the first half of the last century, ...

Factors that drive sexual traits

Nov 26, 2014

Many male animals have multiple displays and behaviours to attract females; and often the larger or greater the better.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.