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🌱 來自: The Neuroendocrine System of the Gut

GI regulatory substances

•   Gastrin:

•   Gastrin-releasing peptide (GRP): Neurocrine. Released from the vagus nerve and act on G cells. Action: Stimulates gastrin release.

•   Histamine: Paracrine. Secreted by mast cells in the stomach. Action: Increases H+ directly and by potentiating effects of gastrin/vagal nerve stimulation.

•   Cholecystokinin (CCK): Hormone. Produced by I cells in the small intestine, stimulated by fatty acids/amino acids. Action: Stimulates pancreatic secretion, gallbladder contraction.

•   Secretin: Hormone. Produced by S cells in the small intestine, stimulated by fatty acids and low pH. Action: Increases pancreatic HCO3- and bile secretion.

•   Glucose-dependent insulinotropic peptide (GIP): Hormone. Produced by K cells in the small intestine, stimulated by fatty acids, amino acids, and oral glucose. Action: Decreases gastric acid secretion, increases insulin release.

•   Vasoactive intestinal polypeptide (VIP): Neurocrine. Released by the parasympathetic ganglia in the intestine, stimulated by stomach distention and the vagal nerve. Action: Stimulates pancreatic HCO3- secretion, inhibits H+ secretion, promotes relaxation of sphincters.

•   Somatostatin: Paracrine. Produced by D cells, stimulated by vagal stimulation and low pH. Action: Decreases gastric acid secretion, gallbladder contraction, and pancreatic secretion.