Why do some people eat so much? It may be because of a hormone in the brain that controls eating for sheer pleasure, rather than hunger, according to new research at Rutgers University. The work could lead to targeting the brain to quell the growing obesity epidemic, according to the researchers. As Zhiping Pang, an assistant professor at Rutgers' Robert Wood Johnson Medical School, explained to Seth Augenstein of Laboratory Equipment, "Certain traits are very similar to drug addiction. If we can target one specific pathway in the brain, it would be fantastic" (http://www.biosciencetechnology.com/news/2015/07/hormone-brain-could-cause-overeating-says-rutgers-science?et_cid=4702150&et_rid=45505806&type=cta)
According to the National Center for Biotechnology Information, in an article called "The hypothalamus, hormones, and hunger: alterations in human obesity and illness, by AP Goldstone, " Obesity is a major global epidemic, with over 300 million obese people worldwide, and nearly 1 billion overweight adults. Being overweight carries significant health risks, reduced quality of life, and impaired socioeconomic success, with profound consequences for health expenditure. The most successful treatment for obesity is gastric bypass surgery, which acts in part by reducing appetite through alterations in gut hormones. Circulating gut hormones, secreted or suppressed after eating food, act in the brain, particularly the hypothalamus, to alter hunger and fullness. Functional neuroimaging studies, using PET and fMRI, will also allow us to tease apart the hormonal and brain pathways responsible for controlling human appetite, and their defects in obesity" (http://www.ncbi.nlm.nih.gov/pubmed/16876568).
The hormone under investigation at Rutgers is called as glucagon-like peptide-1, or GLP-1. Prior research has indicated that the GLP-1 amino acids, secreted by the small intestine and the brain, "chemically tell the brain when the body is satisfied and should stop eating." The researchers explained the effects of the hormone in certain parts of mouse brains. When they reduced GLP-1 levels, the mice overate and ate fattier foods. When the researchers raised the hormone levels, the mice stayed away from fatty foods and only ate when they were hungry, according to an article that was published in the journal Cell Reports.
While GLP-1 therapies exist, including Saxenda, approved by the FDA in December, the drug is a full-body treatment that may cause side effects on the kidneys and liver. The Rutgers researchers are looking at neurons in the mesolimbic dopamine system, a reward circuit, that offer an acute target for new drugs, according to Pang. As he said, "If we can find a specific target, we would have a better therapy."
Additionally, the target could have further implications, Pang added. He explained that the area of the brain affected by GLP-1 is also the place where drug and alcohol addiction are neurologically centered. "The chemical foundations of urges could be subject to further investigation there, he said.
