The main difference between gastrin, secretin, and cholecystokinin is that the stomach secretes gastrin, whereas the duodenum secretes secretin and cholecystokinin.
Gastrin, secretin, and cholecystokinin are three major gastrointestinal hormones. They belong to the endocrine system that controls the digestive function.
Key Areas Covered
1. What is Gastrin
– Definition, Release, Function
2. What is Secretin
– Definition, Release, Function
3. What is Cholecystokinin
– Definition, Release, Function
4. Similarities Between Gastrin Secretin and Cholecystokinin
– Outline of Common Features
5. Difference Between Gastrin Secretin and Cholecystokinin
– Comparison of Key Differences
6. FAQ: Gastrin Secretin and Cholecystokinin
– Answers to frequently asked questions
Key Terms
Cholecystokinin, Gastrin, Secretin
What is Gastrin
Gastrin is a peptide hormone whose primary function is to enhance gastric mucosal growth, secretion of hydrochloric acid into the stomach, and gastric motility. G cells of the gastric antrum and duodenum produce gastrin. Vagal and gastrin-releasing peptide (GRP) stimulation is the primary cause of releasing gastrin. Meanwhile, ingesting peptides, amino acids, elevated stomach pH, and gastric distention are secondary causes of gastrin release. Paracrine inhibition by somatostatin and decreased stomach pH are the causes of reducing gastrin release.
Figure 1: G Cells
What is Secretin
Secretin is another peptide hormone with three functions: gastric acid, regulation of pancreatic bicarbonate, and osmoregulation. S cells in the duodenal mucosa produce secretin. Gastric acid is responsible for the release of secretin. It allows the movement of the duodenal lumen.
Secretin acts on the pancreas, increasing the pancreatic and biliary bicarbonate secretion. Also, it decreases gastric H+ secretion. Further, it increases the secretion of bicarbonate-rich pancreatic fluid. The secretion of bicarbonate aids in the neutralization of gastric pH into pH 6 to 8, which is essential to fat digestion.
Furthermore, secretin plays a similar role to angiotensin II in the brain by being involved in osmoregulation.
What is Cholecystokinin (CCK)
Cholecystokinin is another primary gastrointestinal hormone important in stimulating pancreatic secretion, gallbladder contraction, and gastrointestinal motility. I cells of the duodenal mucosa secrete cholecystokinin. Ingestion of protein and fat significantly increases the levels of cholecystokinin.
Figure 2: CKK Function
In the brain, cholecystokinin increases anxiety and panic disorders.
Similarities Between Gastrin Secretin and Cholecystokinin
- Gastrin, secretin, and cholecystokinin are three hormones in the endocrine system.
- They are peptides.
- They control the function of the digestive system.
Difference Between Gastrin Secretin and Cholecystokinin
Definition
Gastrin refers to a hormone that stimulates the secretion of gastric juice and is secreted into the bloodstream by the stomach wall in response to the presence of food. In contrast, secretin refers to a hormone released into the bloodstream by the duodenum (especially in response to acidity) to stimulate secretion by the liver and pancreas. Meanwhile, cholecystokinin is a hormone secreted by cells in the duodenum and stimulates the release of bile into the intestine and the secretion of enzymes by the pancreas.
Secretion
The stomach secretes gastrin, while the duodenum secretes both secretin and cholecystokinin.
Type of Cells
G cells of the gastric antrum and duodenum produce gastrin, S cells in the duodenal mucosa produce secretin, while I cells of the duodenal mucosa secrete cholecystokinin.
Function
Gastrin stimulates the release of hydrochloric acid in the stomach, and secretin and cholecystokinin stimulate the production of alkaline bicarbonate.
FAQ: Gastrin Secretin and Cholecystokinin
How do gastrin cholecystokinin CCK and secretin influence digestion?
Gastrin, secretin, and cholecystokinin are three hormones released into the gastrointestinal system. They release different enzymes promoting digestion.
What are the effects of the hormones gastrin cholecystokinin and secretin?
Gastrin increases acid and pepsin secretion from gastric mucosa and decreases bicarbonate secretion. Cholecystokinin increases pancreatic enzyme secretion and gallbladder contraction. Meanwhile, secretin increases pancreatic gallbladder and water secretion.
What are the three main hormones that regulate digestion?
Gastrin, secretin, and cholecystokinin are the three gut hormones regulating digestion. They are bioactive peptides.
Conclusion
In brief, gastrin, secretin, and cholecystokinin are three hormones in the endocrine system. Their function is to control the digestive function. The stomach secretes gastrin. Also, it stimulates the release of hydrochloric acid in the stomach. In comparison, duodenum secretes secretin and cholecystokinin, and they stimulate the production of alkaline bicarbonate. Therefore, the main difference between gastrin, secretin, and cholecystokinin is their secretion and function.
References:
- Prosapio JG, Sankar P, Jialal I.Physiology, Gastrin. [Updated 2023 Apr 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
- DiGregorio N, Sharma S. Physiology, Secretin. [Updated 2023 May 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
- Cleveland Clinic medical. “Cholecystokinin: Hormone Function & Definition.” Cleveland Clinic, Accessed 10 Jan. 2024.
Image Courtesy:
- “Control-of-stomach-acid-sec” By File history English Wikipedia – Own Work (CC BY SA 3.0) via Commons Wikimedia
- “Effects of CCK on the gastrointestinal tract” By McortNGHH (CC BY SA 4.0) via Commons Wikimedia
Leave a Reply