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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: J Vasc Interv Radiol. 2015 Mar 14;26(5):613–624. doi: 10.1016/j.jvir.2015.01.017

Figure 3. Hormonal changes during the Fasting vs. Fed States.

Figure 3

Several hormones are released from the Gastrointestinal tract. The ‘hunger hormone’ ghrelin is secreted from X/A Cells in the gastric fundus, whereas PYY and GLP-1 are secreted from L cells, primarily from the ileum and colon. Leptin is primarily produced in adipocytes. During fasting, decreased food intake suppresses the release of PYY, GLP-1 and CCK from the gut while stimulating the secretion of ghrelin by the stomach. Fasting also decreases serum leptin levels. These changes are detected by the brain, leading to hunger. Dieting results in a gut hormone profile that mimics the fasted state. During and after regular feeding, there is a reduction in the production of ghrelin by the stomach. In contrast, production of PYY, GLP-1 and CCK from the gut is increased, and serum leptin levels also rise. These changes, which are detected by the brain, result in decreased appetite and a feeling of satiety.

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