EDMONTON (CUP)—A discovery made by University of Alberta pharmacology professor and Heritage Medical scientist Dr. Bill Colmers has taken a bite out of the question of what makes us hungry. Colmers and his colleagues found a hormone called ghrelin in the hypothalamus, the area of the brain known to control appetite. Ghrelin was thought only thought to be produced in the stomach. Colmers’ study of ghrelin in the brain led him to discover the hormone causes and coordinates the release of neuro-peptide Y (NPY), another brain chemical that causes hunger. The interaction between the two is responsible for increased appetite. The information emerged from his previous research with NPY. Colmers explained that ghrelin acts like a key and NPY like a lock. When ghrelin binds with NPY, it releases the hormone that signals hunger. His findings were published in the scientific journal Neuron on Feb. 20.
“It’s been an interesting set of discoveries that we’ve been able to expand upon,” Colmers said. It’s also a set of discoveries that may help combat a growing threat to public health. Last year, Statistics Canada reported 47.9 per cent of Canadians are overweight (have at least 25 per cent body fat). By studying the signals in the brain that cause the sensations of hunger and satiation, Colmers hopes to ultimately develop a weight-loss treatment people can use while maintaining a regimen of exercise and healthy diet. “What we’re trying to do is get a better handle on what it is that tells the brain we’re hungry, that we want to eat instead of saying we’re really full,” he said. “If you’ve had a big meal, generally you can’t look at food for a while. So what are the signals that work in the the brain to cause the sensation that comes about?” But Colmers doesn’t expect a ghrelin miracle diet pill to appear anytime soon. “People would like to have it, but I don’t know if ghrelin receptors are the right target,” he said. “My guess is that a single pill probably won’t do it so far. Maybe it will, I’m constantly surprised, but my guess is that it will be a combination of medicines and other behavioural modifications, like learning to be more sensitive to signals that your body is full and combining that with a sensible diet which we all supposedly know is good for you. But people don’t buy into it. Even if we could suppress appetite with pills for a long time, in the long run it probably wouldn’t be good for you.” Colmers expects it will be another 20 years before there is a breakthrough diet treatment. “When ghrelin was discovered, there was a great to-do about it, but this paper shows that even if you know about something, you still don’t know a whole lot about it, how it works.” But ultimately, Colmers said the study is important for its contribution to understanding fundamental energy drives and energy balance. “Two of the most important things an animal can do is acquire enough food and then reproduce. Everything else is basically a luxury, if you think in evolutionary terms. The more we understand about how this ancient and important system works, the more we’ll understand about how the brain works and how the brain interacts with the body.”
