Biology

Researchers Found A Chemical That Turned Sedentary Mice Into Furry Little Athletes

No, you're not reading a grocery-store tabloid: researchers really did discover a chemical compound that's being called "exercise in a pill." They found that mice that were given a regular dose of something called GW1516 (explains why it needed a nickname) not only had better running endurance, but were also more resistant to gaining weight. If it does the same for humans, it could be a godsend for people who are unable to exercise.

The chemical formula of GW1516.

This Way To The Gene Show

Say you're a couch potato who wants to train for a marathon. Your first few weeks of running feel like an utter slog—you're out of breath, you're red in the face, and your heart feels like it's going to burst out of your chest. But as you keep to your exercise schedule, running gets easier. That's because your body has made adaptations to keep itself healthy during your fitness kick. In order to give your cells the energy they need for your morning runs, your system becomes more sensitive to insulin. You may also lose fat. Most noticeable of all, though, is your gradual boost in endurance—you'll be able to run for longer without tiring. Scientists have theorized that this endurance increase is due to a shift in what your muscles use for fuel: instead of burning carbohydrates in the form of glucose, you start to burn more fat.

Still, scientists haven't really known how this works. In the past, researchers from the Salk Institute found a clue: when a gene called PPARD (read PPAR delta) was permanently activated in mice, they gained greater endurance, insulin sensitivity, and resistance to weight gain. Basically, they became furry little athletes. The researchers activated that gene through genetic engineering, but they found that they could administer the aforementioned GW1516 (GW) compound to mice to activate the gene, too. Unfortunately, those studies found that GW only affected endurance when the mice exercised daily—not exactly "exercise in a pill." Luckily, that's not the end of the story.

Mouse muscle fibers: oxidative slow-twitch is blue, oxidative fast-twitch is green, and glycolytic fast-twitch is red.

Time To Hit The Tiny Treadmill

For a study published in the journal Cell Metabolism in May 2017, Salk researchers demonstrated a breakthrough. They gave sedentary mice a higher dose of GW for twice the length of time—eight weeks instead of four. Then, they put the treated mice and untreated mice on treadmills (yes, there are treadmills for mice) and watched how long they could run before they were exhausted. For both groups, exhaustion set in when blood sugar hit a critical point: 70mg/dl of glucose, showing that fatigue occurs when blood sugar runs low. But while the untreated mice could run for about an hour and 40 minutes, the treated mice could run for—wait for it—four and a half hours. That's 70 percent longer. According to the study press release, "In addition to having increased endurance, mice who were given the drug were also resistant to weight gain and more responsive to insulin than the mice who were not on the drug."

While this might sound like the next big thing in weight-loss trends, its potential human benefits involve more than giving regular people effortless bikini bods. There are many people who can't exercise, whether due to medical conditions or physical limitations. If physicians could give those people a pill that helps their body make the adaptations it usually would through exercise, it could mean big boosts in health and quality of life. It should be noted that this is just an animal study, so there's no guarantee that the same would be true of humans. And yet...what if it is?

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Written By
Ashley Hamer
May 24, 2017