The small intestine itself doesn't produce a significant amount of hormones. While there are some cells within the lining of the small intestine that produce local hormones (also known as paracrine hormones) that act within the intestinal tissue, the main hormones regulating digestion are produced in other organs and travel to the small intestine to exert their effects.

Here's a breakdown:

1. Local Hormones:

* Cholecystokinin (CCK): This hormone is released by the small intestine in response to the presence of fat and protein. It stimulates the release of bile from the gallbladder and pancreatic enzymes from the pancreas.

* Secretin: This hormone is released by the small intestine in response to the presence of acidic chyme (partially digested food) from the stomach. It stimulates the release of bicarbonate from the pancreas, which neutralizes the acid.

* Gastric Inhibitory Peptide (GIP): This hormone is released by the small intestine in response to glucose and fat. It inhibits gastric emptying and stimulates insulin release.

2. Hormones produced elsewhere but acting on the small intestine:

* Gastrin: Produced in the stomach, it stimulates the release of gastric acid and pepsinogen.

* Insulin and Glucagon: Produced by the pancreas, they regulate blood sugar levels. Insulin promotes the uptake of glucose by the cells, while glucagon stimulates the breakdown of glycogen (stored glucose) in the liver, releasing glucose into the blood.

It's important to note: The small intestine plays a crucial role in digestion and absorption of nutrients, but its hormonal contribution is mainly through the release of local hormones that regulate its own function and coordinate with other organs involved in digestion.