What is the Difference Between Secretin and Cholecystokinin?

Secretin and cholecystokinin (CCK) are two main gastrointestinal (GI) hormones that play crucial roles in the digestive process. They are secreted by the duodenum, specifically, secretin by the S cells and CCK by the I cells. Here are the key differences between secretin and cholecystokinin:

1. Functions: Secretin stimulates the release of an alkaline pancreatic fluid that neutralizes stomach acid as it enters the intestine. On the other hand, CCK stimulates gallbladder contraction, increasing the flow of bile salts into the intestine. In the pancreas, secretin stimulates the secretion of bicarbonate (HCO3), while CCK stimulates the secretion of digestive enzymes.
2. Structure: Secretin is a linear peptide comprising 27 amino acids, while CCK is a peptide hormone that exists in three types, consisting of 33, 59, and 385 amino acid sequences.
3. Target Organs: Secretin mainly targets the pancreas and kidneys, where it is involved in water homeostasis. CCK mainly targets the pancreas and gallbladder, where it is involved in the secretion of digestive enzymes and bile.

In summary, secretin and cholecystokinin are duodenal hormones that play essential roles in the regulation of stomach secretions, maintaining an alkaline environment, and facilitating the digestion of food. They have different functions, structures, and target organs, but they work together to ensure the proper functioning of the digestive system.

Comparative Table: Secretin vs Cholecystokinin

Secretin and cholecystokinin (CCK) are both duodenal peptide hormones that play crucial roles in the digestive process. Here is a table highlighting the differences between them:

Both secretin and CCK are involved in the regulation of stomach secretions and maintaining an alkaline environment in the duodenal contents. However, they differ in their origins, structure, and specific functions in the digestive process.