Appetite, by definition, is a term used to describe ones natural desire for food. It differs from hunger and satiety, and it is affected by a host of neural, hormonal and physical factors that may vary between individuals. This essay sets out to explain how these factors affect the appetite. In doing so the essay will explore the different regions of the brain (and the body) involved in its regulation and control, and the ways in which these areas may be pharmacologically and surgically manipulated to control the appetite itself.
Appetite can be described as ones instinctual desire for food. The smell and sight of food can trigger thoughts that lead to an increased flow of gastric juices in both the mouth and stomach. Sometimes however,…show more content… As a result the body interprets inadequate energy stores and consequently appetite is stimulated[9].
Some researchers have proposed that leptin helps regulate Ghrelin, a peptide hormone released by the empty stomach that stimulates appetite and signals hunger to the brain[10]. Unsurprisingly, Ghrelin levels have been shown to be elevated if someone is under eating and to be depleted in those who overeat. Ghrelin secreted by the empty stomach activates NPY/AgRP neurons, thus stimulating appetite which is only suppressed upon food intake.
Amylin is a naturally occurring hormone that is otherwise known as an islet amyloid polypeptide. It is secreted by the pancreatic beta cells of the Islets of Langerhans, and consists of 37 amino acids. Amylin functions primarily at the area prostema in the brainstem, and works in conjunction with insulin to suppress appetite by suppressing postprandial glucagon secretion and by slowing gastric emptying[11]. However, elevated amylin levels as seen in the obese may decrease the number of surface amylin receptors, making them less sensitive to the amylin and thus lessening its impact on appetite and satiety.
Obestatin is another hormone secreted by the stomach to suppress appetite and food intake[12],[13]. It is a cousin of the hormone Ghrelin, as they both share the same gene but differ in their effects on appetite: where Ghrelin stimulates the
