Somatostatin: characteristics and effects of this hormone

Within the human body we can find a large number and variety of structures and organs that have different properties and functions. The main system in charge of this is the nervous system, but we must also highlight the important role of the endocrine system.

In this sense, a large part of the functions of our body depend on certain hormones altering or regulating the functioning of the organs, glands and tissues that are part of it. Y one of them is somatostatin, which we are going to talk about throughout this article.

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Somatostatin: what is it?

Somatostatin is one of the different hormones that our body secretes naturally, which, like the rest of hormones, acts as messenger that generates some type of alteration in the functioning or in the structure of other systems bodily.

We are facing a protein-type substance that can be synthesized in two different forms, one of twenty-eight amino acids (with greater presence in the digestive tract) and another (the most common in the nervous system and pancreas, and the best known) consisting of a total of fourteen amino acids, and that it has an effect on different body systems such as the nervous, the endocrine or even the digestive or the excretory.

It also acts as a neurotransmitter.

Somatostatin is a fundamentally inhibitory hormone, and its synthesis takes place in the pancreas. It is produced mainly in the islets of Langerhans like insulin and glucagon, specifically by the delta cells of these structures. However, we can also find other areas that synthesize and use it, among which the hypothalamus and other brain nuclei or even the walls of the gastrointestinal tract stand out.

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Main functions of this hormone

Somatostatin is a hormone that can be found in most systems of our body, and that has different effects on it. As we have seen previously, plays a primarily inhibitory role in most target organs.

One of the functions or properties for which it is best known is for its inhibitory role of growth hormone, something that allows this brake to a great extent in adulthood and contribute to the regeneration capacity of our body by reducing the energy expenditure dedicated to grow up. To do this, it acts on the pituitary in such a way that it reduces the production of growth hormone or somatotropin. In fact, this function is what has earned it the name of the hormone that inhibits the release of somatotropin.

It also affects the release of other hormones, such as corticotropin that allows the production of steroids by our adrenal glands. Also affects and inhibits the functioning and synthesis of thyroid hormones, suppressing its releasing factor in the pituitary. In addition, at the pancreatic level, somatostatin generates the inhibition of insulin release and glucagon, something that allows you to control the emission of these hormones and that can cause an increase in blood glucose in blood.

In the digestive tract, it inhibits and reduces intestinal motility and enzyme secretion, as well as the absorption of glucose and other nutrients. It also has an effect on the excretory system, reducing urination. Another of its effects is to reduce blood flow at the splenic or visceral level, as well as salivation or intestinal mucous membranes.

It also has an effect on the immune system, as well as in the cardiovascular. In the nervous system, it inhibits the functioning of part of the central system, as well as the autonomic one (in fact it reduces and hinders movement, by having an effect on the extrapyramidal system). It also inhibits the release of monoamines such as norepinephrine and dopamine.

Pharmacological use: clinical utility

Somatostatin is as we have said a hormone present in our body, which originates mainly in the pancreas. However, some people may have some kind of deficit in their synthesis or find themselves in a medical situation that could benefit from its external management. And is that due to its effects on the body somatostatin also has been synthesized in the laboratory in order to treat various conditions.

The synthetic somatostatin used as a medicine is analogous and has the same chemical composition than that made by our body, and is applicable by infusion into blood, through perfusion. It usually comes in the form of vials with lyophilized powder and ampoules with a solvent (usually sodium chloride) that allows it to dissolve. The dose in question will depend on various factors such as age or the presence of pathologies.

The use of this hormone it is indicated for the treatment of internal bleeding, especially with regard to lesions or ruptures of varicose veins and fistulas in areas such as the esophagus or pancraes, or in the digestive tract.

The reason for this is that, as we have mentioned previously, somatostatin inhibits not only hormones but also also decreases the secretions of the digestive organs, intestinal motility and blood flow in the viscera. However, its use is only to complement other treatments, requiring other types of interventions to achieve clinical improvement.

Besides that, is the treatment of choice for acromegaly or gigantism due to its inhibition of growth hormone and the activity of pituitary. Another clinical application of this hormone occurs in pancreatic or gastric tumors, although in this case it acts more as a marker and as a vehicle for radioactive molecules that can fight against neoplasia, as well as in some of the pituitary gland being an inhibitor of its activity.

Risks and side effects of its medical use

Somatostatin is a very useful hormone both naturally and in its clinical application. Now, in the second case we can find that its use as a drug involves some risks. Sometimes it is contraindicated or, smaller doses than usual must be used.

Among the possible side effects, it is relatively common to development of hyperglycemia, dizziness and hot flashes, abdominal pain and nausea. There may also be episodes of diarrhea, hypoglycemia, bradycardia, and both hypo and hypertension. Finally there is the risk of arrhythmias, blockages and heart problems.

Also decreases the flow of urine and sodium in the blood, as well as glomerular filtration, something that can be negative in people with severe kidney problems. The presence of cardiac alterations should be especially monitored in the first moments of treatment, including monitoring vital signs.

For populations that should not take this drug, somatostatin is contraindicated in pregnant women or during childbirth or lactation (which should be suspended if treatment with this drug is essential) since it affects growth hormone and this can cause alterations in the fetus or baby. Its use in children or adolescents is not recommended either.

Nor should it be mixed with other drugs unless the doctor so indicates, especially in the case of anxiolytics (which potentiates). Obviously, those who suffer from an allergy to somatostatin or any of the components of its preparation should not take this drug.

People with severe kidney failureAlthough they can be treated with this drug, they should do so with lower doses. Since it blocks the release of insulin and glucagon and the risk of it generating hyperglycemia, its pharmacological use must be especially controlled in diabetic people, especially if they are insulin dependent or type 1 (it may be necessary to administer insulin).

Bibliographic references

• Spanish Agency for Medicines and Health Products. (2011). Package leaflet: Information for the user. Somatostatin eumedica 250mcg. 1 Lyophilized Powder Vial + 1 solvent ampoule of 1 ml. Drug information center.
• Kandel, E.R.; Schwartz, J.H. & Jessell, T.M. (2001). Principles of neuroscience. Fourth edition. McGraw-Hill Interamericana. Madrid.
• Ortega, E., Mestrón, A. and Webb, S.M. (2000). Usefulness of somatostatin analogues in gastroenteropancreatic neuroendocrine tumors and non-GH-producing pituitary tumors. Endorinology and Nutrition, 48 (5): 140-148.