Gastrin 17 (basal)

Detailed description of the study

The implementation of basic digestive functions in the body is a complex process that is regulated by the work of a number of gastrointestinal peptides.

Gastrointestinal hormones (peptides) are a group of substances that are produced by glandular cells of the mucous membrane lining the gastrointestinal tract. Insufficient or excessive synthesis of gastrointestinal hormones, which occurs due to a number of pathologies of the digestive system, disrupts normal digestive processes.

One of the representatives of this group of hormones is gastrin. It is synthesized by special endocrine G cells of the gastrointestinal tract. Gastrin acts on specific gastrin receptors in the stomach and stimulates the synthesis of hydrochloric acid. Normally, the secretion of hydrochloric acid increases after eating and then decreases. An increase in the concentration of hydrochloric acid reduces the production of gastrin through a feedback mechanism.

Gastrin also affects the formation of gastric juice, bile and mucus. Regulates the digestive process, affecting the motility of the stomach and small intestine. This hormone also affects the motor activity of muscles in the wall of the stomach and small intestine.

Hypergastrinemia (excessive synthesis of gastrin) occurs due to a number of pathologies of the digestive system (gastritis, peptic ulcer), stress, B12-deficiency anemia and malignant tumors of the stomach.

Excessive synthesis of gastrin (hypergastrinemia) occurs due to pathological changes in the digestive system (hyperplasia of G cells that produce this hormone, with B12-deficiency anemia, benign and malignant neuroendocrine formations of the stomach - gastrinomas).

Due to prolonged hypergastrinemia, Zollinger-Ellison syndrome is formed.

Patients complain of:

Weakness;
Loss of appetite;
Severe pain in the solar plexus area;
Nausea;
Vomiting;
Diarrhea.

During instrumental studies, multiple ulcers can be detected in the stomach, duodenum and small intestine. Benign or malignant gastrinoma (a tumor that produces gastrin) is also diagnosed. Gastrinoma is usually located in the duodenum or pancreas.

Most often, a malignant gastrinoma is diagnosed, which has practically not manifested itself in any way before. Malignant gastrinoma, as a rule, actively metastasizes to neighboring organs and tissues.

Diagnosis of gastrinomas presents certain difficulties, because patients, as a rule, use drugs from the proton pump inhibitor group to suppress the symptoms of the disease.

Laboratory diagnosis is based on determining the level of gastrin in the blood serum in combination with determining the basal level of gastric secretion, conducting provocative tests (with intravenous administration of calcium or synthetic secretin). With gastrinoma, severe hypergastrinemia (more than 150 pg/ml) will be observed.

To clarify the nature of the tumor, it is necessary to conduct an immunohistochemical study, and evaluate the functional activity by reaction with antibodies to the corresponding hormones.

An increase in gastrin synthesis is also provoked by the use of certain medications, these include proton pump inhibitors, antacids, glucocorticoids and others.

Determining the level of gastrin in the blood serum is an important diagnostic test to determine the causes of ulcerative lesions of the gastrointestinal tract and if gastrinoma is suspected. Also, based on the results of the study, the specialist determines the tactics of further therapy.

The main role of the hormone gastrin

This protein is produced by the diffuse (widespread) endocrine system of the digestive tract, its D and G cells. There are several forms that differ in the number of amino acids in the protein chain. Gastrin-34 is produced predominantly by the pancreas, it is the most active, and types with 14 and 17 amino acid residues are synthesized by the stomach and duodenum.

The interaction between gastrin and its receptors in the stomach results in the following biological reactions:

increasing the content of hydrochloric acid in gastric juice, creating an optimal pH for digesting food;
pepsin release;
secretion of mucus and bicarbonate (alkali) to protect the mucous membrane from self-destruction;
slowing down the contractions of the stomach for a deeper breakdown of the components of the food bolus;
stimulation of the production of prostaglandin E (it ensures acceleration of blood circulation), the influx of fluid and leukocytes into the gastric wall. This helps digestion, as these cells secrete a number of enzymes and carry out phagocytosis (absorption of microbes, toxins).

At the end of the first phase of breakdown of food components, gastrin prepares the intestinal stage of digestion, increasing the secretion of:

pancreatic and intestinal enzymes;
somatostatin (suppresses the activity of gastric and then intestinal enzymes);
secretin and cholecystokinin - they ensure the secretion of bile and pancreatic juice.

Thus, gastrin starts the gastric and intestinal digestion of food and stops it after each stage is completed.

We recommend reading the article about the hormone somatostatin. From it you will learn about the main functions of somatostatin, what results from an excess of the pancreatic hormone, the properties of the synthetic analogue and indications for use.

And here is more information about the hormone leptin.

References

Clinical recommendations. Neuroendocrine tumors., approved. Ministry of Health of the Russian Federation, 2021.
Stepanov, Yu.M. Serum gastrin content in patients with reflux gastritis. // Stepanov Yu.M., Mosiichuk L.N., Kovalenko A.N. – Gastroenterology, 2014 No. 2(52). — P. 52-56.
Tereshchenko, I.V. On the issue of diagnosing gastrinoma. – Povolzhsky Oncological Bulletin, 2021. No. 3(40). — P. 56-60.
Schubert, M., Rehfeld, J. Gastric peptides-gastrin and somatostatin. – Comprehensive Physiology, 2021. – Vol. 18;10(1). — P.197-228. doi: 10.1002/cphy.c180035.

Regulation of secretion

The most significant activator of gastrin formation is the entry of food into the stomach, stretching of its walls, as well as the smell and appearance of the dish. The following have a positive effect on hormone release:

the vagus nerve, to a lesser extent - adrenaline and the sympathetic department of the autonomic system;
insulin;
histamine;
high level of calcium in the blood.

Inhibition of secretion occurs under the influence of:

increased acidity of gastric juice. Hydrochloric acid is the main factor that acts on the hormone level according to the feedback principle;
endorphins and enkephalins of the brain (hormones of joy, euphoria);
prostaglandin E;
adenosine (released by brain neurons during relaxation);
thyroid calcitonin;
somatostatin, cholecystokinin and secretin, which provide rest for an empty stomach, help maintain an alkaline environment in the intestines.

Reasons for detection in blood

The main purpose of the gastrin test is to detect its increased secretion in pancreatic tumors - gastrinoma. In almost 90% of cases it is located in the pancreatic islet and is malignant. Its cells intensively produce the hormone, regardless of food intake.

As a result, ulcerative defects of the mucous membrane of the stomach and duodenum, the initial part of the small intestine develop with abdominal pain, sour belching, heartburn, diarrhea, and weight loss (Zollinger-Ellison syndrome).

The reason for diagnosis may also be:

decreased formation of vitamin B12 and Addison-Biermer anemia (crimson tongue, dizziness, general weakness, gait disturbance, urinary incontinence);
a positive test result for Helicobacter pylori (a bacterium involved in the development of peptic ulcers).

Useful video

Watch the video about digestion in the stomach and intestines:

Indications for testing

A study of gastrin levels is prescribed as an element of a comprehensive diagnosis of pathologies of the digestive tract. A referral to the laboratory is given by a gastroenterologist or endocrinologist (if a tumor process is suspected).

Features of the study:

standard preparation: food 12 hours before blood sampling, donate biomaterial on an empty stomach, in the morning,
within two to three days you need to stop taking medications that reduce the acidity of fatty acids,
You should not eat fatty foods the day before the test,
be sure to avoid alcohol for 48 hours,
warn your doctor about taking medications, especially those affecting the gastrointestinal tract.

Find out about the reasons for the increase in growth hormone, as well as how to bring the levels back to normal.
An overview and characteristics of drugs for lowering blood sugar levels can be seen in this article.
On the page https://fr-dc.ru/zabolevaniya/diabet/gestatsionnyj.html read about the rules of following a diet for gestational diabetes mellitus in pregnant women.

Causes of hormonal imbalance

If basal gastrin 17 is elevated, then the reasons for this deviation in most cases lie in the presence of pathologies, which were mentioned earlier. This:

stomach ulcer;
the presence of ulcerative formations on the walls of other organs of the gastrointestinal tract;
gastritis, occurring in an atrophic form;
cancer of the stomach.

Note. Less commonly, hypergastrinemia is observed in patients suffering from renal failure.

The reasons why basal gastrin 17 may be low is a pathological abnormality such as hyperthyroidism. It is accompanied by an increase in the secretion of thyroxine and triiodothyronine - the main thyroid hormones. Such a failure entails a disorder in the gastrointestinal tract, resulting in hypogastrinemia.

Some surgical interventions may also be the reason why gastrin is low. In particular, this applies to gastric resection and antrectomy.