Hormones and Paracrines that Act in Digestion

Vasoactive intestinal peptide VIP

Duodenal hormone that stimulates buffer secretion, inhibits acid production, and dilates intestinal capillaries.

somatostatin

Produced by Pancreatic Islets. Targets insulin-secreting cells to inhibit digestion of nutrients, hence their absorption from gut.

MOTILIN

duodenal mucosa is site of production; Stimulated by fasting Target organ is proximal duodenun Motilin stimulates migrating motor complex

SECRETIN

hormone produced on duodenum wall that stimulates pancreas to release bicarbonate to neutralized acid in duodenum increases bile output

GIP

produced in duodenal mucosa Stimulus: fatty chyme target organs: stomach, pancreas (beta cells) STIMULATES INSULIN RELEASE AND INHIBITS HCL PRODUCTION

Intestinal Gastrin

produced in duodenal mucosa, and is stimulus for production of acidic and partially digested food in duodenum. The target organ is stomach and it stimulates gastric glands and motility

Histamine

produced in stomach mucosa; stimulus for production is food in stomach; target organ is stomach; Histamine activates parietal cells to release HCL

Gastrin

site of production is g cells in stomach mucosa; stimulus for production: food, particularly partially digested proteins in stomach, chemically stimulated by acetylcholine released by nerve fibers. Gastrin increases HCL secretion, stimulates gastric emptying, stimulates contraction of intestinal muscle, relaxes iliocecal valve, stimulates mass movements

CHOLECYSTOKININ (CCK)

site: duodenal mucosa Stimulus: fatty chyme target organs: stomach, liver, pancreas, gallbladder activity: inhibits stomach secretory activity potentiates secretin's actions on liver and pancreas increases output of enzyme rich pancreatic juice stimulates gallblader to store and expel bile

SEROTONIN

stimulates other neurons to release enkephalins; causes contraction of stomach muscle and is produced in stomach mucosa; food in stomach stimulates production.