A key hormone involved in appetite control, called ghrelin, has been identified by researchers from the Oregon Health & Science University(OHSU). Scientists have demonstrated the effect of the hormone on the brain and have shown that the hormone activated the specialized neurons in the hypothalamus involved in weight regulation. Ghrelin is a hormone produced in the stomach with the ability to stimulate feeding when introduced to specialized weight regulating brain cells called neuropeptide Y neurons. Lead author Michael Cowley, Ph.D., added that past research has shown that increasing ghrelin levels in mice for an extended period resulted in weight gain. Ghrelin is believed to be part of the body's natural signaling system which informs the brain when it's time to eat. In both mice and humans, ghrelin levels increase naturally in response to weight loss or reduced caloric intake and the hormone diminishes in response to food intake.
The scientists used a method pioneered by OHSU researchers Cowley, Roger Cone, Ph.D., and Malcolm Low, M.D., Ph.D. to pinpoint and witness the effects of the hormone in the brain. They used a fluorescent protein to highlight certain neurons, making the brain cells distinguishable from other surrounding neurons. They then used tiny electrodes to record cell activity in response to ghrelin. The researchers have also located a new source for ghrelin production in the body. The site is located in a section of the hypothalamus that had no previously known function and that is near the brain region affected by the hormone.
Researchers believed that this new discovery could be used to develop drugs aimed at stimulating appetite in patients who have undergone extreme weight loss due to illness, a condition known as cachexia, and in finding new drugs that would assist children who are developing at a slower than normal rate. On the other hand, drugs aimed at limiting production of the hormone might be developed to reduce appetite for those battling severe obesity. Senior scientist, Cone, also added that future research will help distinguish between the roles of the brain and stomach production sites so that there would be better understanding of weight regulation and energy homeostasis in the body.