Let's learn about Cholecystokinin, the amazing hormone in our body that signals the brain when the stomach is full.

Have you ever eaten a very oily meal, like a biryani, or something like a spicy curry with coconut milk, or a piece of fish with oil? When you finish eating, you think, "Oh, that's enough, my stomach is full." Have you ever wondered who exactly tells your brain that your stomach is full and that you should stop eating? One of the most important functions of this hormone that we are talking about today is cholecystokinin. Simply put, it is like a very important manager in our digestive system.

Simply put, what is cholecystokinin?

Cholecystokinin is a hormone that works as part of our digestive system. A hormone is a chemical messenger that is produced in one place in our body, travels through the blood, and carries a message to another place. Like a postman. This cholecystokinin, or CCK for short, is released by our body after we eat, when that food is digested.

It is mainly produced and released in our small intestine . But the amazing thing is, this CCK hormone is also present in our brain and central nervous system. But doctors are still trying to find out a lot about its function there. Sometimes it is also called pancreozymin . But the most common name used is cholecystokinin.

How does this CCK hormone start to be released from the body?

Imagine you eat food. That food first goes into the stomach. After some digestion in the stomach, that food then goes into the first part of the small intestine. We call it the duodenum .

That's where the real work begins. If you've eaten a meal rich in protein (e.g. meat, fish, eggs, lentils) and fat (e.g. oil, coconut milk, butter), a special type of cell in the walls of the duodenum (called 'I-cells') "recognizes" these proteins and fats. It's like a guard seeing a special guest.

What are the main things that happen inside the body due to the CCK hormone?

Once CCK is in the blood, it doesn't just sit there. It's like a manager for the entire digestive system, doing several jobs at once. This is a very amazing process. Let's see what it is.

Effects of CCK on the brain and nervous system

In addition to digestion, research has found that CCK also affects our mental state. Specifically, anxiety and panic disorders.It seems that CCK is related to anxiety. Studies have shown that increased levels of CCK in the brain can increase anxiety. Further research is ongoing on this.

What medical conditions may be associated with CCK?

Doctors have observed that people with certain medical conditions have low levels of CCK. However, it is not yet clear whether this is a cause of the disease or a symptom of the disease.

• Gastroparesis: In this condition, the stomach muscles do not function properly, causing food to be delayed in moving from the stomach to the small intestine. Low levels of CCK may be involved.
• Biliary Dyskinesia: This is when the gallbladder does not contract properly and release bile. This may be due to the gallbladder not responding properly to CCK.
• Anxiety and obesity: Some people have genetic variations that alter the way the CCK hormone communicates with the brain. This can lead to changes in appetite control signals or anxiety control signals.

The relationship between CCK and obesity

This is an important topic for many people. Scientists are doing a lot of research on the relationship between CCK and obesity.

It has also been found that some obese people have less sensitivity to the "fullness" signal sent by the CCK hormone. This means that even though they are full, their brains may not be able to accurately sense it. This can lead to them eating more than they need. CCK and another hormone called leptin work together to control our hunger and fullness signals.

What is the Cholecystokinin Test?

Sometimes, if your doctor suspects that your gallbladder is not working properly, he or she may order a special test to see if it is working properly. This is when the CCK test is done.

This is usually done in conjunction with a HIDA scan . A HIDA scan is a special scan that looks at the function of things like our gallbladder and bile ducts.

Here's how to do it:

1. Tracer Injection: First, a technician will inject a very small amount of a radioactive substance (tracer) into your vein. Don't worry, this is not harmful to the body. This substance travels through the bloodstream and collects in your liver and gallbladder.

2. First scan:Then, a series of images of your gallbladder are taken using a computer scanner.

3. CCK injection: Next up is the most important part. If the doctor wants to see what happens when your gallbladder contracts, they will inject you with a small amount of the hormone CCK through a vein.

4. The second scan: After the CCK injection, what happens is the same as when you eat a fatty meal. That is, your gallbladder starts to contract. At that point, they take another series of pictures.

By comparing these images, the doctor can determine exactly how well your gallbladder is functioning, whether it is releasing bile properly, and whether there are any blockages.

Is CCK used for medical treatment?

Currently, the CCK hormone is not used directly as a treatment for any medical condition. However, it has become very important for discovering and testing new drugs.

For example:

• Weight loss drugs: Because CCK has the ability to sense fullness, researchers are trying to develop appetite-suppressing drugs that can mimic that process.
• Anxiety treatment: A specific part of CCK (CCK-4) can induce anxiety and panic in humans under controlled conditions. Scientists use this method to test the effectiveness of new drugs that are intended to reduce anxiety.

So, CCK is not just another hormone in our bodies. It's an amazing chemical messenger that affects a wide range of things, from our digestive system to our mental health, and there's a lot more to be discovered in the future.