Definition
- The secretin family of gastrointestinal hormones comprises structurally related gut peptide hormones: secretin, GIP, VIP and glucagon (enteroglucagon).
- Secretin was the first hormone to be discovered (Bayliss and Starling, 1902).
Secretin Family Hormones and Their Actions
Secretin family GI hormones, source cells and principal actions
Hormone
Secretin
- Source cells
- S cells, upper small intestine
- Principal actions
- Bicarbonate-rich (watery, alkaline) pancreatic secretion; alkaline bile secretion; decreases gastric acid secretion and motility; contracts pyloric sphincter
GIP
- Source cells
- K cells, duodenum and jejunum
- Principal actions
- Decreases gastric secretion and motility; stimulates insulin secretion
VIP
- Source cells
- Mucosal cells and nerves, entire GIT (mainly colon)
- Principal actions
- Increases intestinal water/electrolyte secretion; vasodilation; decreases GI motility; decreases gastric acid secretion
Glucagon (enteroglucagon)
- Source cells
- A cells (pancreas), L cells (intestine)
- Principal actions
- Hyperglycemia; GLP-1 stimulates insulin secretion