By Medical Discovery News

Oct. 27, 2012

Anyone with a TV has seen them – the skinny, smiling men and women who claim to have lost weight without breaking a sweat thanks to diet pills. But most diet pills carry health risks like increased blood pressure and heart rate, insomnia, and stomach cramps. Some carry more risks than others, such as Orlistat, which was taken off the market after people developed liver failure.

Yet even that didn’t dash the hopes of dieters searching for a magic pill, which could be pinned on a completely new approach – a hormone that boosts a person’s desire to exercise. Swiss scientists found that when a hormone called erythropoietin (EPO) was elevated in the brains of mice, they were more active.

EPO is the same performance-enhancing hormone banned by various sporting events and leagues including the Olympics and the Tour de France. During the 1998 Tour race, personnel from several teams were caught red-handed with thousands of doses of EPO and other banned substances.

Athletes are tempted to use EPO because it has the ability to increase red blood cells in the bloodstream, which translates to more oxygen circulating throughout the body and consequently better physical performance. The hormone exists naturally, produced by cells in the kidney that can sense when oxygen levels start to dip.

EPO travels in the bloodstream and into bone marrow where it binds with receptors to stimulate red blood cell (erythrocyte) production. Medically, EPO is used to treat certain forms of anemia. Since EPO accelerates erythrocyte production, it increases the blood’s capacity for carrying oxygen.

Even though the body makes EPO, using more of it comes with risks. In the past 15 years, about 18 cyclists have died suddenly in their sleep from using EPO. When injected repeatedly in small doses, EPO stimulates the release of more red blood cells. In some cases, too many red blood cells are produced, which can thicken the blood, clog capillaries, and lead to a stroke or heart attack. Athletes face a greater risk since they tend to become dehydrated, further thickening the blood.

However, researchers at the University of Zurich found that when given in acute high doses (500 – 2,000 times more than what athletes use), EPO crossed the blood-brain barrier and helped mice run better. The mice had not produced more red blood cells nor increased their cardiovascular capacity. So EPO acted as a brain hormone that motivated the mice to exercise more, without changing their physiology.

Beyond helping many Americans who are obese, EPO may quicken recovery for people who have been bedridden and need to rebuild muscle mass. This treatment approach has not yet been tried on humans, so it will take time for researchers to determine its effects and efficacy.

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