Summary
Gastrin, secretin and cholecystokinin coordinate digestive secretions and motility.
In depth
Gastrin stimulates stomach acid; secretin triggers bicarbonate release from the pancreas; CCK stimulates bile release and enzymes; ghrelin signals hunger; GLP-1 enhances insulin and promotes fullness, used in obesity and diabetes drugs.
Hormones coordinate digestion. Ghrelin rises before meals, leptin signals long-term fat stores. Gut hormones influence appetite and glucose.
Remember: the gut is the largest endocrine organ.
Hormones from enteroendocrine cells coordinate digestion: gastrin (G cells, stimulated by peptides and stretch) increases HCl; secretin (S cells in duodenum, stimulated by acid) triggers bicarbonate-rich pancreatic juice; CCK (I cells, stimulated by fat and protein) causes gall bladder contraction and enzyme release and signals satiety; GIP and GLP-1 are incretins that enhance insulin release; ghrelin from the stomach stimulates hunger, and leptin from fat tissue and PYY from the ileum signal fullness.
Bayliss and Starling discovered secretin in 1902 and coined the word hormone. GLP-1 analogues (semaglutide) treat diabetes and obesity. Zollinger-Ellison syndrome is a gastrin-secreting tumour causing ulcers. Gut hormones also interact with the brain through the vagus.
Example: eating a fatty meal triggers CCK and explains why the gall bladder contracts.
Frequently asked questions
What is Gut Hormones?
Gastrin, secretin and cholecystokinin coordinate digestive secretions and motility.
Which area of biology covers Gut Hormones, and how advanced is it?
Gut Hormones is one of the 51 topics in Human Physiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Blood Glucose Regulation, Energy Balance and Metabolism, Digestive Enzymes.
Can you give an example of Gut Hormones?
Semaglutide mimics GLP-1.
What should I learn before Gut Hormones?
Work through the Beginner topics in Human Physiology first, such as Homeostasis, Tissues and Organs, Skeletal System, then return to Gut Hormones. Advanced topics assume the Intermediate vocabulary.
What topics are related to Gut Hormones?
The closest topics to Gut Hormones are Blood Glucose Regulation, Energy Balance and Metabolism, Digestive Enzymes, Digestive System. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Gut Hormones?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Gut Hormones. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Gut Hormones different from Blood Glucose Regulation?
Gut Hormones: Gastrin, secretin and cholecystokinin coordinate digestive secretions and motility. Blood Glucose Regulation: Insulin lowers and glucagon raises blood glucose through negative feedback. Read both side by side and note what each one explains.
How should I study Gut Hormones step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Blood Glucose Regulation and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.