Phenylethylamines or catecholamines - what is it? These are active substances that act as intermediaries in intercellular chemical interactions in the human body. These include: norepinephrine (norepinephrine), adrenaline (epinephrine), which are hormonal substances, as well as dopamine, which is a neurotransmitter.
general information
Catecholamines - what is it? These are several hormones that are produced in the adrenal glands, its brain substance, and enter the bloodstream as a response to an emotional or physical stressful situation. Further, these active substances take part in the transmission of nerve impulses to the brain, provoke:
- the release of energy sources, which are fatty acids and glucose;
- dilated pupils and bronchioles.
Norepinephrine increases blood pressure directly by narrowing the blood vessels. Adrenaline acts as a stimulant of metabolism and speeds up the heartbeat. After hormonal substances do their work, they break down and, together with urine, are excreted from the body. Thus, the functions of catecholamines are that they provoke the endocrine glands to work actively, and also contribute to the stimulation of the pituitary gland and hypothalamus. Normally, the amount of catecholamines and their metabolites is contained in small quantities. However, under stress, their concentration increases for a while. In some pathological conditions (chromaffin, neuroendocrine tumors), a huge amount of these active substances is formed. Tests can detect them in the blood and urine. In this case, the following symptoms appear:
- increased blood pressure for a short or long period;
- very severe headaches;
- trembling in the body;
- increased sweating;
- prolonged anxiety;
- nausea;
- slight tingling in the limbs.
An effective method of treating tumors is considered surgical intervention aimed at its removal. As a result, the level of catecholamines decreases, and the symptoms decrease or disappear.
Mechanism of action
The effect is the activation of membrane receptors located in the cellular tissue of target organs. Further, protein molecules, changing, trigger intracellular reactions, due to which a physiological response is formed. Hormonal substances produced by the adrenal glands and thyroid gland increase the sensitivity of receptors to norepinephrine and adrenaline.
These hormonal substances affect the following types of brain activity:
- aggressiveness;
- mood;
- emotional stability;
- reproduction and assimilation of information;
- quick thinking;
- participate in shaping behavior.
In addition, catecholamines provide energy to the body. A high concentration of this complex of hormones in children leads to their mobility, cheerfulness. As they grow older, the production of catecholamines decreases, and the child becomes more restrained, the intensity of mental activity decreases slightly, possibly a worsening of mood. By stimulating the hypothalamus and pituitary gland, catecholamines contribute to an increase in the activity of the endocrine glands. Intense physical or mental stress, at which the heartbeat increases and the body temperature rises, lead to an increase in catecholamines in the blood stream. The complex of these active substances acts rapidly.
Types of Catecholamines
Catecholamines - what is it? These are biologically active substances, which, thanks to their instant response, allow the body to work ahead of schedule.
- Norepinephrine. This substance has another name - the hormone of aggression or rage, as it gets into the bloodstream, provokes irritability and increased muscle mass. The amount of this substance is directly related to great physical overload, stressful situations, or allergic reactions. Excess norepinephrine, having a narrowing effect on the vessels, has a direct effect on the speed of circulation and blood volume. The person's face acquires a red tint.
- Adrenalin. The second name is the hormone of fear. Its concentration increases with excessive experiences, physical and mental stress, as well as with severe fright. This hormonal substance is formed from norepinephrine and dopamine. Adrenaline, constricting blood vessels, provokes an increase in pressure and affects the rapid breakdown of carbohydrates, oxygen and fats. The face of the individual acquires a pale appearance, endurance with strong excitement or fright increases.
- Dopamine. The hormone of happiness is called this active substance, which is involved in the production of norepinephrine and adrenaline. It has a vasoconstrictive effect on the body, provokes an increase in the concentration of glucose in the blood, inhibiting its utilization. It inhibits the production of prolactin, and affects the synthesis of growth hormone. Dopamine affects libido, sleep, thought processes, joy, and pleasure in eating. An increase in the excretion of dopamine from the body along with urine is detected in the presence of tumors of a hormonal nature. In the brain tissue, the level of this substance rises with a lack of pyridoxine hydrochloride.
The biological effect of catecholamines
Adrenaline significantly affects cardiac activity: enhances the conductivity, excitability and contractility of the myocardial muscle. Under the influence of this substance, blood pressure rises, and also increases:
- strength and heart rate;
- minute and systolic blood volume.
Excessive concentration of adrenaline can provoke:
- arrhythmia;
- in rare cases, ventricular fibrillation;
- violation of oxidation processes in the heart muscle;
- changes in metabolic processes in the myocardium, up to dystrophic changes.
Unlike adrenaline, norepinephrine does not have a significant effect on cardiac activity and causes a decrease in heart rate.
Both hormonal substances:
- They have a vasoconstrictive effect on the skin, lungs and spleen. In adrenaline, this process is more pronounced.
- The coronary arteries of the stomach and heart expand, while the effect of norepinephrine on the coronary arteries is stronger.
- They play a role in the metabolic processes of the body. Adrenaline predominates in effect.
- Contribute to the decrease in muscle tone of the gallbladder, uterus, bronchi, intestines. Less active in this case is norepinephrine.
- They cause a decrease in eosinophils and an increase in neutrophils in the blood.
When is a urine test prescribed?
Analysis for catecholamines in the urine makes it possible to identify disorders that, due to pathological processes, lead to a disruption in the normal functioning of the body. The causes of failures can be various serious diseases. Assign this type of laboratory research in the following cases:
- To control therapy in the treatment of a chromaffin tumor.
- With a neuroendocrine or detected adrenal neoplasm, or a genetic predisposition to tumor formation.
- With hypertension, which is not treatable.
- The presence of hypertension with persistent headache, heart palpitations and increased sweating.
- Suspicion of a chromaffin neoplasm.
Urine test preparation
Determination of catecholamines helps confirm the presence of pathological processes in the human body, for example, high blood pressure and oncology, as well as make sure the treatment of pheochromocytoma and neuroblastoma is effective. For accurate results of the analysis, you should undergo training, which consists in the following:
- Two weeks before the procedure, do not take medicines that affect the increased secretion of norepinephrine from the ends of the adrenergic nerves, in consultation with the treating doctor.
- For two days, do not drink drugs that have a diuretic effect. Exclude tea, coffee, alcohol-containing drinks, cocoa, beer, as well as cheese, avocados and other exotic vegetables and fruits, all legumes, nuts, chocolate, all products that contain vanilla.
- For a day and during the collection of daily urine, avoid any overstrain, exclude smoking.
Immediately before collecting urine for analysis on catecholamines, conduct genital hygiene. Biological material is collected three times a day. The first morning portion is not taken. Three hours after this, urine is taken, the second time - after six and then, after 12 hours. Before being sent to the laboratory, the collected biomaterial is stored in a sterile container, placed in a special box or refrigerator, at a certain temperature. On the container for collecting urine indicate the time of the first and last emptying of the bladder, personal data of the patient, date of birth.
Urine analysis for catecholamines
In the laboratory, biomaterial is examined for several indicators that depend on the age and gender of the individual. The unit of measurement of hormones is mcg / day, each species has its own norms:
- Adrenalin. Allowed values for citizens over 15 years old are 0-20 units.
- Norepinephrine. The norm for the age category of 10 years is 15-80.
- Dopamine. The indicator corresponds to normal values of 65-400 at the age of 4 years.
Various factors influence the outcome of a urinary catecholamine study. And since pathology in the form of a chromaffin tumor is quite rare, it is often false positive. For the purpose of reliable diagnosis of the disease, additional types of examinations are prescribed. In case of detection of an increased content of catecholamines in patients with an already established diagnosis, this fact indicates a relapse of the disease and the ineffectiveness of the therapy. It should be remembered that taking certain groups of drugs, stress, taking alcohol, coffee and tea affects the final result of the research. Pathologies in which an increased concentration of catecholamines is detected:
- liver disease
- hyperthyroidism;
- myocardial infarction;
- angina pectoris;
- bronchial asthma;
- peptic ulcer of the duodenum or stomach;
- head injury;
- prolonged depression;
- arterial hypertension.
A low level of hormonal substances in urine indicates diseases:
- kidney
- leukemia;
- various psychoses;
- adrenal gland underdevelopment.
Preparation for a blood test for catecholamines
14 days before the delivery of the samples, it is necessary to exclude drugs containing sympathomimetics (in agreement with the treating doctor). For two days, exclude from the diet: beer, coffee, tea, cheese, bananas. Stop smoking per day. For 12 hours, refrain from eating.
Blood is taken through a catheter, which is installed the day before sampling the biomaterial due to the fact that a puncture of a vein also contributes to an increase in the concentration of catecholamines in the blood.
Panel "Catecholamines of blood" and serotonin + urine analysis for GVK, VMK, 5-OIUK
Using such a panel, the content of catecholamines is determined: serotonin, dopamine, norepinephrine, adrenaline and their metabolites. Indications for the purpose of this study are as follows:
- determination of the causes of hypertensive crises and arterial hypertension;
- in order to diagnose neoplasms of the nervous tissue and adrenal glands.
More information can be obtained by appointing an analysis of daily urine to determine the level of catecholamines due to the fact that their synthesis in this period is influenced by:
- pain;
- cold;
- stress;
- injuries
- heat;
- physical stress;
- asphyxia;
- any types of loads;
- bleeding
- use of narcotic drugs;
- lowering blood glucose.
With diagnosed arterial hypertension, the concentration of catecholamines in the blood approaches the highest level of normal indicators, and in some cases it increases by about two times. In a stressful situation, adrenaline in blood plasma increases tenfold. Due to the fact that catecholamines in the blood are fairly quickly neutralized, it is appropriate to detect them in urine to diagnose pathological conditions. Practicing doctors prescribe tests for the concentration of norepinephrine and adrenaline mainly for the diagnosis of hypertension and pheochromocytoma. In young children, in order to confirm neuroblastoma, it is important to determine the metabolites of norepinephrine and adrenaline, as well as dopamine.
In order to obtain reliable information about catecholamines in the analysis of urine, the presence of their decomposition products is also determined: GVK (homovanilinic acid), VMC (vanillyl mindic acid), normetanephrine, methanephrine. The excretion of metabolic products normally exceeds the excretion of a complex of hormonal substances. The concentration of methanephrine and IUD in urine is greatly overestimated with pheofromocytoma, which is important for diagnosis.
Vanillyl mindic acid is a decay product of adrenaline and norepinephrine, they are found in a daily analysis for catecholamines. Indications for the purpose of the analysis are neuroblastomas, tumors and evaluation of the adrenal glands, hypertension and crises. The study of this metabolite allows us to conclude on the synthesis of adrenaline and norepinephrine, and also assists in the diagnosis of neoplasms and the evaluation of the adrenal medulla.
Serotonin
In oncological practice, an indicator in the blood such as catecholamine serotonin is important for the detection of argentaffin, a special type of tumor. It is considered one of the mediators of inflammation and is a highly active biogenic amine. The substance has a vasoconstrictor effect, takes part in the regulation of temperature, respiration, pressure, kidney filtration, stimulates smooth muscles of the intestines, blood vessels, bronchioles. Serotonin can cause platelet aggregation. Its content in the body is detected using the metabolite of 5-OIUK (hydroxyindoleacetic acid) urine. Serotonin content is increased in cases of:
- a carcinoid tumor of the abdomen with metastases;
- hypertensive crises in the diagnosis of pheochromocytoma;
- neuroendocrine tumors of the prostate, ovary, intestines, bronchi;
- pheochromocytomas;
- metastasis or incomplete removal of the neoplasm after surgery.
In the body, serotonin is converted to hydroxyindoleacetic acid and leaves with urine. The concentration of this substance in the blood is determined by the amount of excreted metabolite.
Catecholamines - what is it? These are useful substances for any individual, necessary for an instant response of the body to an irritant: stress or fear. A blood test shows the presence of hormones immediately at the time of taking the biomaterial, and a study of urine - only the previous day.