Answer
Appetite seems to be regulated by peptide hormones and certain chemical pathways. Among the regulatory hormones of appetite and body weight are some that have been designated gut brain peptides. This name has been applied to these substances because they function as chemical messengers between gastro-intestinal tract and the brain. Examples of gut brain peptides are the hormones ghrelin, peptide yy(PYY), and cholecystokinin (CCK).
Work Step by Step
Ghrelin, which is secreted in the stomach, stimulates appetite (hunger). Polypeptide YY(PYY) is secreted by the neuroendocrine cells of the ileum and colon; this gut brain peptide promotes satiety. Cholecystokinin
(CCK), the third member of this group, is the best known; it is secreted by neuroendocrine cells of the duodenum and the ileum; this hormone causes release of bile from the gall bladder; it also promotes secretion of pancreatic juice. In addition, CCK inhibits stomach emptying, and induces feelings of satiety by signaling the satiety center of the ventromedial hypothalamus.
