ABSTRACT
The gastrointestinal (GI) hormones are a large and complex group of peptides that are synthesized by endocrine cells in the mucosal lining of the gut. There are some general features of the GI endocrine system which pose particular challenges in understanding nutritional control of gene expression. Gastrin has two major physiological roles, the stimulation of gastric acid secretion and stimulation of mucosal growth in the acid-secreting portion of the stomach. Fasting results in parallel decreases in antral gastrin concentrations and antral gastrin mRNA. It's clear that additional studies are required to establish definitively that the effects of nutrients on antral gastrin mRNA are mediated at the level of gene transcription and to elucidate the precise stimuli and molecular mechanisms that underlie these effects. Cholecystokinin (CCK) is structurally related to gastrin but derives from a different gene. Prolonged fasting produces a gradual and progressive decline in CCK mRNA.
