A peptide hormone, gastrin naturally occurs in the human body. The cells forming stomach's lining produce the hormone gastrin. This hormone works to control the release of digestive acids in the stomach. While several other hormones are also involved in secreting digestive acids, gastrin is the main controller of stomach acids. The cells in the stomach that produce gastrin hormone are known as G cells.
Gastrin works to stimulate gastric acid (HCl) secretion in the stomach. The gastric acid is produced by the stomach's parietal cells. This hormone also helps in gastric motility. The G cells of the stomach produce and release gastrin in the pyloric antrum (also known as gastric antrum) of the stomach, the pancreas and duodenum.
In 1905, scientists discovered gastrin in gastric antrum extracts and, in 1964, it was identified as a pair of heptadecapeptides. Until the 1970s, scientists believed that only the antroduodenal cells produced gastrin and the primary function of this peptide hormone was to regulate secretion of gastric acids.
However, now scientists are aware of the structure of gastrin as well as gastrin receptor genes and also their extensive appearance outside the stomach. In addition, today gastrin is known to be a growth factor. Hence, gastrin regulates fundic mucosa cells' growth and also appears to have an impact on the development of epithelial mucosal cells in other parts of the body.
It is an established fact that when we eat any food, it kindles the production of gastrin. The mechanism works like this - when an individual eats anything, the food goes into the stomach, which activates the G cells to encourage secretion of this peptide hormone into the bloodstream. As the levels of gastrin start rising in the bloodstream, it encourages the secretion of gastric acids. The gastric acids facilitate digestion of ingested foods. In due course, sufficient gastric acid is produced by the cells lining the stomach and when this happens, the levels of gastrin in the bloodstream start falling again.
Apart from the stomach, gastrin also plays a role in various other organs of our body. For instance, this peptide hormone helps the liver, intestines and pancreas. However, the effects of gastrin in these organs are not as pronounced as in the stomach. Gastrin works to activate digestive enzyme production in the pancreas. On the other hand, this hormone helps in the production of bile in the liver. In the intestine, gastrin works to facilitate food movement throughout the lower region of our digestive tract.
Gastrin possesses the ability to kindle several aspects of growth and mucosal development in the stomach. Gastrin is also used in the form of a medication to encourage DNA, RNA and synthesis of proteins in the gastric mucosa. At the same time, treatment using gastrin helps to augment the parietal cell's number. It has also been observed that people with abnormally high gastrin levels (a condition known as hypergastrinemia) constantly demonstrate gastric mucosal hypertrophy.
Occasionally, it becomes necessary for physicians to test the amount of gastrin produced in an individual's body. For instance, such test may be undertaken when the doctor suspects that individual is enduring ailments related to the digestive system. In addition, the check-up may also be undertaken to verify if the individual has any abnormal growth in his/her pancreas or even in the cells that make up the lining of the stomach. Tests may be performed to check a person's gastrin production to ascertain whether he has any tumour in his intestine. Such check-ups may also help to discover existence of certain ailments like pernicious anemia (a disease related to blood).
Medical professionals generally carry out an intravenous secretin test to ascertain the level of gastrin in an individual's bloodstream. This test involves taking the patient's blood sample and subsequently injecting secretin - a digestive hormone - into any of his/her veins.
A second blood sample is obtained after the patient has been injected with the digestive hormone secretin. More samplings follow at intervals of five minutes for about 15 minutes following the injection. Thirty minutes after injecting secretin, medical professionals take another blood sample of the patient. The findings of the tests are usually made available in a few days after the tests.
Normally, elevated levels of gastrin in the bloodstream may suggest the patient is suffering from some blood-related disease or has tumours, but gastrin tests may reveal many other things related to this peptide hormone. For instance, high gastrin levels may also indicate specific types of ulcers and kidney failure. Then again, low levels of gastrin in the bloodstream may also hint at a number of medical conditions. For instance, poor gastrin levels have usually been related to hypothyroidism (an under active thyroid).
Gastrin is a peptide hormone, which stimulates the stomach to make stomach acid. This hormone is released into the bloodstream when an individual eats something and undigested food starts entering the stomach. High levels of this hormone in the bloodstream suggest that the individual may be suffering from many disease and health conditions. High levels of gastrin may be due to specific stomach ailments or it may also be a sign of a malignant tumour that produces this hormone. Therefore, if a physician suspects that his/her patient is suffering from some gastrointestinal problems, he/she should recommend for a laboratory test to ascertain the level of gastrin and ascertain whether the patient is really suffering from any ailment or medical condition.
When an individual has high level of gastrin in his/her bloodstream, they are said to be suffering from a condition called hypergastrinemia. The reasons for having high levels of gastrin in the blood is classified into two classes - either an ailment or medical condition is responsible for the body producing additional gastrin; or a neoplasm is responsible for the additional production of this hormone. Whichever may be the case, the objective of the treatment should not only be to lower the gastrin level, but also cure the original cause. If it is possible to cure the underlying cause, the levels of this peptide hormone will once again become normal.
Often, various stomach conditions, for instance, obstruction of gastric outlet and even autoimmune gastritis, may be responsible for elevated levels of gastrin in the bloodstream.
Distention of the stomach may also cause the gastrin level to rise in the bloodstream. Sometimes side effects of other medical conditions may also result in the gastrin level to be high. For instance, laboratory tests have shown that conditions like diabetes mellitus, rheumatoid arthritis and pernicious anemia (a disease related to blood) may also be responsible for elevated levels of gastrin. In addition, whenever there is an increase in the pH level of the stomach, for instance gastric ulcers, it will trigger the stomach to produce and release extra gastrin.
It is worth mentioning here that high levels of gastrin is among the three diagnostic decisive factors for developing Zollinger-Ellison syndrome, which is a grouping of one or additional hypergastrinemia, gastrinomas and acute ulcer disease. Precisely speaking, gastrinomas are basically tumours that ooze gastrin, thereby raising the level of this hormone in the body. Such tumours generally appear in the duodenum or the pancreas. Roughly 50 percent of all gastrinomas are all malignant tumours.
When other health conditions are absent, diagnostically hypergastrinemia is an indication of one or several gastrinomas. Apart from Zollinger-Ellison syndrome, sometimes tumours may also develop owing to pituitary adenomas or hyperthyroidism. Moreover, gastrinomas can develop even in the absence of any predisposing medical condition. Some people may also have high levels of gastrin which may occur in their bloodstream as a result of colon cancer or renal failure.
A fasting blood test is used to measure the levels of gastrin in the bloodstream. This peptide is released in the stomach only when one consumes food and it enters the stomach. Hence, a non-fasting blood test will be of no use when trying to measure gastrin levels. Quite a few drugs like aspirin, opiates and even protein pump inhibitors possess the ability to get in the way of testing gastrin levels and result in inaccurate readings. Hence, before testing gastrin levels by means of a fasting blood test, a physician will usually tell the patient how many days in advance of the examination he or she needs to discontinue using these medications.