Ever had that meal that just… sits wrong? Or maybe a nagging burn in your chest that pops up a bit too often, making you wonder what’s really going on in there? It’s easy to just chalk it up to “something I ate,” but sometimes, there’s a deeper story unfolding in your digestive system. And one of the main characters in that story is a little hormone called gastrin. It might be small, but believe me, it’s a powerhouse when it comes to how your gut works. I see folks in my clinic fairly often trying to figure out these kinds of tummy troubles, and sometimes, gastrin is part of the conversation.
What is Gastrin and What Does It Do?
So, what exactly is gastrin? Think of it like a tiny, very efficient director for parts of your digestion. It’s a hormone – a chemical messenger that travels through your bloodstream, telling different parts of your body what to do and when. Gastrin has a few really important jobs:
- It tells your stomach to release gastric acid (you might know it as hydrochloric acid). This acid is crucial for breaking down food.
- It gets the muscles in your stomach moving – this is called gastric motility, and it helps mix and churn your food.
- It encourages the lining of your stomach (we call this the mucosa) to keep renewing itself, which is important for protection.
- It also works with another hormone, cholecystokinin, to signal your gallbladder and pancreas to contract and release their digestive juices. Teamwork!
Now, you might hear “gastrin” and “gastric acid” and think they’re the same. Not quite. Gastrin is the hormone, the signal. Gastric acid is one of the things released because of that signal. Gastric acid then activates a digestive enzyme called pepsin. Together, they’re key ingredients in your gastric juices, helping to break down proteins.
The Journey of Gastrin: Production and Control
It’s pretty neat how our bodies manage all this. Your digestive system is smart!
Where is Gastrin Made?
Gastrin isn’t made just anywhere. It comes from special cells called G-cells (easy to remember – G for gastrin!) found in the lining of your digestive organs.
Most of this gastrin comes from your stomach, specifically the lower part of it (called the antrum). But your duodenum (that’s the first part of your small intestine, right after your stomach) and your pancreas also chip in and make some.
What Kicks Gastrin into Action?
Your brain and your gut are constantly chatting through a network of nerves called vagal nerves. So, even just thinking about food can get the gastrin-release process started!
Once you actually start eating, other signals jump in:
- A rise in pH levels in your stomach (meaning it’s less acidic, ready for food).
- The stretching of your stomach walls as food arrives.
- The presence of certain foods, especially proteins. They really get gastrin going!
And your stomach listens. Gastrin tells it to release acid and get those muscles moving.
And What Tells Gastrin to Settle Down?
Your body doesn’t want gastrin working overtime. Once food moves from your stomach into the duodenum for the next stage of digestion, things start to change.
As food leaves and acid levels in your stomach rise (because the job is done for now), gastrin production eases off. Then, your digestive system releases another hormone called somatostatin. Think of somatostatin as the “off-switch” for gastrin and other digestive hormones. Pretty clever, huh?
When Gastrin Levels Go Awry: Symptoms and Signs
Now, like anything in the body, sometimes the balance of gastrin can be off. If your gastrin levels get too high (hypergastrinemia), it often means your stomach is producing too much stomach acid. And that can lead to some uncomfortable symptoms. You might experience:
- A burning or gnawing pain in your stomach, especially between meals or at night.
- Chronic heartburn and indigestion – that uncomfortable feeling after eating.
- Acid backwash or regurgitation, where stomach contents come back up.
- A chronic sore throat or hoarseness from the acid irritation.
- Chronic diarrhea.
- General digestive difficulties or discomfort.
If these sound familiar, especially if they’re frequent or have been around for a while, it’s always a good idea to chat with a doctor.
Investigating High Gastrin: Tests and What They Mean
If you’re dealing with persistent tummy troubles, and we’re trying to piece together why, one of the things we might look at is your gastrin levels.
The Gastrin Test
There’s a straightforward blood test for this, simply called a gastrin test. A small sample of your blood is taken and sent to a lab to measure the amount of gastrin circulating. It’s usually done after you’ve been fasting for a bit.
Why Do Gastrin Levels Matter?
While low gastrin levels are pretty rare, high gastrin levels (hypergastrinemia) can be a clue. Sometimes, it means there are gastrin-secreting tumors (called gastrinomas) present, often in the pancreas or duodenum. These can be noncancerous or, sometimes, cancerous.
Other times, high gastrin can be a sign that something is reducing the amount of stomach acid. When acid is low, the body tries to compensate by releasing more gastrin to stimulate acid production, but the “off-switch” signals don’t work as well.
What Can High Gastrin Levels Do?
Too much gastrin often leads to too much stomach acid. This excess acid can be harsh on the delicate lining of your stomach and duodenum. Over time, it can erode this lining, leading to ulcers (this is called peptic ulcer disease). It can also worsen or contribute to chronic acid reflux (you might know this as GERD, or gastroesophageal reflux disease).
If you have peptic ulcer disease or GERD that isn’t getting better with the usual medications, we might consider checking your gastrin levels.
Conditions Linked to High Gastrin Levels
It can be a bit of a puzzle sometimes, but high gastrin levels can point us toward a few different situations:
- High Gastrin and High Stomach Acid:
- Zollinger-Ellison syndrome: This is a condition where gastrinomas cause the stomach to produce way too much acid.
- Multiple endocrine neoplasia type 1 (MEN1): This is a genetic condition that can lead to tumors in various endocrine glands, including those that produce gastrin.
- Chronic kidney failure: Kidney issues can sometimes affect hormone clearance.
- Gastric outlet obstruction (GOO): If food can’t easily leave the stomach, it can sometimes trigger more gastrin.
- High Gastrin and Low (or Normal) Stomach Acid:
- Atrophic gastritis: This is when the acid-producing cells in your stomach lining have wasted away (atrophied). Major causes include:
- H. pylori infection: A common bacterial infection of the stomach.
- Autoimmune disease: Where the body’s immune system mistakenly attacks the stomach cells.
- Acid-blocking medications: Long-term use of medications like H2 blockers or proton pump inhibitors (PPIs) can lead to the body trying to compensate by making more gastrin.
- Vagotomy: A surgical procedure that involves cutting parts of the vagus nerve (sometimes done for severe ulcers) can reduce acid production and, in turn, raise gastrin.
It’s a lot to take in, I know. But figuring out the “why” behind high gastrin is key to getting the right treatment.
Key Takeaways About Gastrin
Let’s boil it down. Here are a few important things to remember about gastrin:
- Gastrin is a key hormone that helps manage your digestion, mainly by telling your stomach to release acid.
- It’s produced by G-cells in your stomach, duodenum, and pancreas.
- Things like thinking about food, food in your stomach, and changes in stomach acidity can trigger its release.
- High gastrin levels (hypergastrinemia) can sometimes cause problems, often by leading to too much stomach acid.
- A gastrin test (a blood test) can check your levels.
- Conditions like Zollinger-Ellison syndrome, atrophic gastritis, or even long-term use of certain acid-reducing meds can be linked to high gastrin.
- Symptoms like persistent stomach pain, severe heartburn, or chronic diarrhea might warrant a look at your gastrin levels.
We’ll always discuss all the options and what these tests might mean for you or your loved one.
You’re not alone in figuring these things out. If something feels off with your digestion, please don’t hesitate to reach out. We’re here to help.
