Ghrelin

         Ghrelin is a hormone typically referred to as the ‘hunger hormone’ because it stimulates your brain to increase your appetite and your ability to store food. This hormone is produced in the PDI cells located in your stomach lining, otherwise known as the pituitary gland. After this water-soluble, 28 amino acid peptide is created, it can be released through the pancreas, small intestine, brain or stomach. It is released when there is an absence of food, and therefore an absence of energy. It has a simple neuroendocrine pathway, which allows it to attach to a sensory neuron in the hypothalamus, a small section of the brain, which is responsible for controlling appetite. Sensory neurons are neurons that convert external stimuli, such as chemical hormones, to internal stimuli. This sensory neuron will then secrete a growth hormone into the blood system. This new hormone will then connect to an endocrine cell, causing a release of a different stimulus, which eventually attach to its target effectors. This is the part of the cycle that finally causes the stimulation of appetite and increase in ability to store food. This cycle is actually called a negative feedback loop, meaning that when energy decreases, the amount of Ghrelin increases to counteract this deficit. Once a sufficient amount of food has been eaten, Ghrelin production will stop for the time being. A large amount of Ghrelin can also be caused by fasting or increased exercise.

Works Cited

Stengel, Andreas and Taché, Yvette. “Ghrelin – A Pleiotropic Hormone Secreted from Endocrine X/A-Like Cells of the Stomach.” US National Library of Medicine. National Institutes of Health, 12 Feb. 2012. Web. 27 February 2014.

"You & Your Hormones.” Society for Endocrinology, 2011. Web. 27 February 2014.

"Balancing Your Hunger Hormone." Infinity Medical Systems. 2005. Web. 1 March 2014.