What is Secretin?

Mary McMahon
Mary McMahon

Secretin is a hormone produced in the duodenum which plays an important role in the digestive process and also appears to be involved in osmoregulation, the process the body uses to keep the internal balance of salt and fluids stable. This hormone can also be introduced into the body, usually in a test which is designed to check on the function of the pancreas. Secretion for injection or introduction to the body through a gastric tube is available from several pharmaceutical companies, by prescription only.

If the glucose content of a food is high, secretin will stimulate the production of insulin to handle the glucose.
If the glucose content of a food is high, secretin will stimulate the production of insulin to handle the glucose.

A cascading series of reactions happen when people start to digest food. Secretin is one of the many players involved. As food moves through the stomach, it transitions into a partially digested state known as chyme. Chyme is very acidic as a result of the gastric juices it has been marinating in, and when it starts to be pushed into the intestines, secretin kicks into action.

A secretin test may be given to a person to see how their pancreas responds.
A secretin test may be given to a person to see how their pancreas responds.

One of the things secretin does is trigger the production of bicarbonates which are used to neutralize the acid in the chyme so that it does not damage the intestines. Unlike the stomach, the intestines are not equipped to deal with the harsh gastric juices used in the early stages of digestion. The release of secretin also tells the stomach to stop making gastric juices, indicating that the next phase of digestion is beginning and that the stomach can take a break.

As food moves through the stomach, it transitions into a partially digested state known as chyme.
As food moves through the stomach, it transitions into a partially digested state known as chyme.

Secretin also triggers the production of pancreatic juices and liver bile, which are used to lubricate the chyme as it moves through the digestive tract. Additionally, if the glucose content of the food is high, secretin will also stimulate the production of insulin to handle the glucose.

Secretin triggers the production of pancreatic juices, which are used to lubricate the chyme as it moves through the digestive tract.
Secretin triggers the production of pancreatic juices, which are used to lubricate the chyme as it moves through the digestive tract.

In the secretion stimulation test, a patient will be injected with secretin to see how the pancreas responds. If stimulation with this hormone does not result in the production of pancreatic juices, it indicates that the patient has a medical issue which needs to be identified and treated. This test can be uncomfortable, as the secretin is often introduced through a stomach tube, and many people gag during the placement and removal of the tube.

Secretin, a hormone produced in the duodenum, plays an important role in the digestive process.
Secretin, a hormone produced in the duodenum, plays an important role in the digestive process.

This hormone has another distinction: It was the first hormone identified. Researchers working with the digestive tract in the early 1900s noted that this compound appeared to play an important role, sending chemical signals to moderate the digestive process. This contradicted the expectation that the digestive process was mediated by the nervous system, changing the way that scientists thought about the body and paving the way to the discovery of other “chemical messengers,” which came to be called hormones.

A cascading series of reactions happen when people start to digest food.
A cascading series of reactions happen when people start to digest food.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments

SunSeal

Secretin doesn't really have anything to do with having your gallbladder out. Yes, you will have an over production of bile if it's removed, but secretin is produced in the duodenum and does have a serious effect for people who undergo intestinal surgery and lose the duodenum.

SunSeal

Just wanted to say, if anyone gets their gallbladder out to ask your doctor about secretion and overproduction of bile. It is a serious side effect that everyone I talk to is surprised about. It's like doctors don't even mention it.

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