Endocrinology: hormones, adenoma hypophysis, pituitary tumor

(adrenal gland, suprarenal gland, adrenal gland) paired endocrine glands located in the retroperitoneal space above the upper pole of kidneys at XI-XII thoracic vertebra. Each adrenal gland consists of an inner medulla and outer cortex, which are two different origin, structure and functions of the glands, united in the process of phylogenesis in a single body. Along with the kidneys, N. enclosed in adipose capsule and covered with renal fascia.
N. Right in the adult has a triangular shape, the left - lunate (Fig. 1). The lower surface of the right N. and verhneperednyuyu surface of the left AN peritoneum covers. The adrenals are covered with a thin fibrous renal capsule (fascia Girot). Own a connective tissue capsule N. flabby exterior and dense at the surface. From inside the prostate capsule N. depart trabeculae - bundles of connective tissue fibers, blood vessels and nerves. The length of AN adult ranges from 30 to 70 mm, width - from 20 to 35 mm in thickness, from 3 to 8 mm. Total weight of both adrenal glands is an average of 13-14 g, cortical substance of 9 / 10 the mass of the adrenal glands.
N. The blood supply is implemented by three groups of adrenal arteries: upper, middle and bottom, penetrating into the iron in the form of numerous capillaries, which are widely anastomose with each other and form the medulla of enlargement - a sine wave. The outflow of blood from the NG is through the central and multiple superficial veins draining into the venous network surrounding organs and tissues. Parallel blood are lymphatic capillaries, efferent lymph. Innervated by sympathetic N. (mostly) and the parasympathetic fibers of the splanchnic, vagus and phrenic nerves.
Cortical substance AN consists of secretory cells, arranged in such a way that they acted in secret capillaries. In the cortical substance distinguish three zones (Fig. 2). Immediately beneath the capsule is glomerular zone, whose cells resemble cylindrical, they are grouped in small clusters of irregular shape, separated by capillaries. Under the glomerular zone is a broad beam area, its polygonal cells form bands, or columns, directed radially. Between these columns are capillaries. In-stream zone distinguish the outer part, formed the most crowded major lipids of cells and the inner part, formed by a small dark cells. The third zone of the cortical substance - net - a relatively thin and its cells form strands going in different directions, and anastomosing with each other. In their cytoplasm often contained lipofuscin granules.
Cortical substance AN - a vital organ. Generated is of steroid hormones, synthesized mainly from cholesterol - Corticosteroid hormones and a small number of sex hormones - are involved in the regulation of metabolism and energy (metabolism and energy). In extracts from the bark of AN identified about 50 steroids, but the blood is allocated only a part. Others are biosynthetic precursors, metabolites or intermediates (intermediates in the biosynthesis) evolved into the blood of steroid hormones. Diverse effects kortikosgeroidov for all types of metabolism, vascular tone, immunity, etc. make cortical substance N. key sector of life support the body under normal conditions and in conditions of adaptation to various stresses (see Stress). In the glomerular zone of the cortical substance is synthesized aldosterone - the main mineralocorticoid, participates in the regulation of water-salt metabolism (water-salt exchange). In the area of the beam are synthesized mainly by cortisol and corticosterone - glucocorticoids, affecting protein, fat and carbohydrate metabolism (see nitrogen metabolism, fat metabolism, carbohydrate metabolism) and the exchange of nucleic acids (nucleic acids). Sex hormones, mainly androgens, are formed in the net zone. Synthesis of corticosteroids, especially glucocorticoids, and sex hormones is regulated by ACTH (see pituitary hormones).
Medulla in the center of NM (Fig. 3) and is surrounded by a cortical substance, from which it is not sharply delimited. Glandular cells of the brain substance (Fig. 4) are called chromaffin or feohromnyh, because selectively stained with salts of chromium in the yellow-brown color. In addition to glandular cells in the brain substance AN lot of nerve fibers and nerve cells. Clusters of chromaffin cells, the so-called paraganglia (see Apud-system), are also found in the course of the pulmonary trunk, ascending and abdominal aorta in the mediastinum, there is a lumbar aortic chromaffin body chromaffin and other cells secrete three hormones (epinephrine, norepinephrine and dopamine), on their chemical nature are catecholamines (Catecholamines). Biosynthetic precursor of these hormones is the amino acid tyrosine (see Amino Acids). Adrenaline is synthesized only in the NA, noradrenaline and dopamine, are also formed in the paraganglia and numerous neurons of the sympathetic nervous system. All tissues that produce catecholamines, are Adrena-lovuyu system. The biological action of catecholamines varied. They cause an increased concentration of glucose in the blood and stimulate the hydrolysis of fat (lipolysis). Adrenaline increases the systolic blood pressure, strengthens the contractions of the heart, dilates blood vessels of skeletal muscles, relaxes the smooth muscles of bronchi, together with corticosteroids it contributes to heat buildup in your body. Norepinephrine increases the diastolic blood pressure, increases coronary arteries of the heart, reduces heart rate. Release into the bloodstream of biologically active substances from chromaffin cells cause various stimuli originating from the environment and internal environment (cooling, physical activity, emotions, arterial plyutenziya, hypoglycemia, and others).
Methods. Informative methods for determining the functional state of NM is the definition of the concentration of adrenal hormones and their metabolites in blood and urine, as well as a number of functional tests. Glucocorticoid function N. evaluate the content of 11-hydroxycorticosteroids in the blood and free cortisol in urine. Androgenic and glucocorticoid function of N. partially determined on the daily excretion of free and dehydroepiandrosterone and its sulfate in urine. Becoming increasingly important radioimmunological method for determining cortisol in the blood and free cortisol in urine. Studies conducted in the morning on an empty stomach, when the concentration of cortisol in the blood is maximal, and at 23 h, when it is reduced to about 2 times. Breach rhythm of cortisol release into the bloodstream indicates pathology N. radioimmunoassay method is also used to determine the concentration of aldosterone and renin activity (the main regulator of aldosterone synthesis) in blood plasma. As the functional tests most widely dexamethasone test, allowing a dose of dexamethasone to differentiate a tumor emanating from the adrenal cortex and adrenal cortex hyperplasia associated with excessive production of ACTH (pituitary - Cushing), on the other, clinically similar conditions ( gapotalamichesky syndrome, etc.), or differentiated tumor of the adrenal cortex of their bilateral hyperplasia. If you suspect a functional insufficiency of N. a stimulating samples with AKTG1-24. In the case of a large adrenal insufficiency stimulating samples may affect health of patients, so these tests carried out in hospital. To assess the state of mineralocorticoid function H. serum concentration of potassium and sodium. In severe adrenal insufficiency sodium content in the blood decreases, and potassium - is increasing, hyperaldosteronism, by contrast, is characterized by hypokalemia. On the functional status of brain substance N. judged by the concentration of catecholamines in the blood or urine.
In the diagnosis of diseases using X-ray methods AN: Pnevmoretroperitoneum, tomography (tomography), angiography (angiography), aortography with catheterization of adrenal veins and the determination of the concentration of hormones in blood samples. The most modern methods of investigation are N. Ultrasound, radionuclide scanning, computed tomography and magnetic resonance imaging. With their help determine the size and shape of AN (Fig. 5), establish a tumor.
Pathology N., usually leads to a violation of their steroidogennyh functions (a general reduction or increase, loss of or increase in the synthesis of one or several steroid hormones, etc.). Reduction or complete cessation of the functions of the cortex AN may be a result removal of one or both AN and AN injury in any pathological process (tuberculosis, amyloidosis, sarcoidosis, autoimmune processes, hemorrhage, etc.) or loss of ACTH-pituitary function. Cushing with excess synthesis of glucocorticoids may be due to hypertrophy and (or) hyperplasia (diffuse or diffusely nodular) cortex N. resulting hyperstimulation bark N. pituitary ACTH, such as Itsenko - Cushing's disease (Itsenko - Cushing's disease) or tumor, ie, ACTH ectopic origin (with small cell lung cancer, etc.). The cells of the cortical substance N. In all these cases reveal a high functional activity. The cause of Cushing's at Itsenko - Cushing's syndrome is a unilateral swelling of the cortex hyperplasia N. Isolated glomerular area or the whole cortex and cortex of both N. adenomatosis may cause hyperaldosteronism nonneoplastic origin.
Genetically caused by defects of enzymes involved in the biosynthesis of corticosteroids in most cases lead to a breach of the biosynthesis of cortisol, which causes an enhanced secretion of ACTH and the development of secondary hyperplasia and hypertrophy of cortical NA, the severity of which depend on sex, congenital deficiency of enzymes and the patient's age, in which manifested genetic defect. Children with virilizing variant of congenital adrenal hyperplasia (congenital adrenal hyperplasia), the mass of the adrenal cortex from birth to adolescence may be at 5-10 times the mass of the adrenal cortex of healthy children.
Clinical manifestations of disease caused by N. decline (gipokortitsizm) or increase (hypercorticoidism) synthesis of adrenal hormones as compared with the norm. Primary chronic gipokortitsizm most pronounced form is observed in Addison 's disease (Addison's disease). A similar clinical syndrome develops also after bilateral removal of adrenal glands - a total adrenalectomy. Violation of the regulatory function of the hypothalamus and (or) the Pituitary Body with the decrease in blood ACTH release (see the hypothalamic-pituitary insufficiency) leads to the development of secondary gipokortitsizma. When reducing the synthesis of aldosterone may be a so-called isolated gipoaldosteronizm - a disease characterized by general weakness, arterial plyutenziey, bradycardia, prone to fainting and collapse, hyperkalaemia. The clinical picture with hemorrhages in the AN, acute inflammatory processes and the destruction of NA as a result of tuberculosis, syphilis, adrenal lesions characterized by acute development of adrenal insufficiency. Its main symptoms are abdominal pain, high body temperature, dysfunction of the gastrointestinal tract, cyanosis of the skin, nervous excitement, collapse, in severe cases - coma. Cushing's associated with an increased synthesis of adrenal hormones, hormonally active tumor cortex NM or its hyperplasia. Tumors originating from the cortical substance N., mostly mixed, producing different hormones. Tumors secreting mainly glucocorticoids, are solitary, almost always unilateral. The tumor cortex N. vary from 2 to 30 cm in diameter, weight - from a few grams up to 2000-3000. Hyperplasia N., caused by an excess of ACTH, is the cause of pituitary - Cushing, a tumor originating from the cortical substance N. (kortikosteroma) - Itsenko syndrome - Cushing. A peculiar pathology of the cortical substance AN is congenital adrenal hyperplasia, in which inadequate synthesis of cortisol stimulates the increase of production of ACTH and androgens. The predominance of production of androgens and the development virilnogo syndrome (Virilny syndrome) are observed in tumors androsteromah-synthesizing male sex hormones. For tumors originating from the glomerular zone of the cortical substance - aldosteroma (Conn syndrome, or primary hyperaldosteronism), characterized by an increased concentration of aldosterone in the blood and decrease in activity of renin in the blood plasma. Aldosteroma constitute about 25% of all tumors originating from the bark of N. This is usually solitary tumor diameter from 0,5 to 3 cm, are rarely bilateral or even multiple sites. Histologically differentiated aldosteroma originating mainly from the glomerular or fascicular zone, and aldosteroma mixed structure originating from elements of all areas of the cortex, including mesh zone. The bulk of the tumor cells filled with lipids, mainly esterified cholesterol. Malignant aldosteroma constitute 2-5% of all aldosterom. In rare cases it may be kortikoestroma - a tumor originating from the cortex NA and produce female sex hormone estrogen. At the same men appear feminine traits: increased mammary glands, a redistribution of body fat disappear libido and potency. In rare cases kortikoestrom women of reproductive age are the main symptom of metrorrhagia. Often, hormone production of tumors is mixed, ie they are synthesized as gluco-and mineralocorticoid, and sex hormones. Among these tumors, more than half are malignant. Tumors of the adrenal cortex, producing androgens, leading to the development virilnogo syndrome (Virilny syndrome) in women.
Chromaffinoma (chromaffinoma), secreting large amounts of catecholamines, come from chromaffinopathy medulla N., and para-aortic paraganglia, paraganglia cells of the bladder or the mediastinum. In addition to the hormonally-active tumors in the NM may experience non-functioning benign tumors (lipoma, fibroma, etc.) and malignant tumors (hormone-active, non-functioning and the so-called pyrogenic cancer of the adrenal cortex). Benign tumors AN are small, asymptomatic, usually discovered accidentally. Malignant non-functioning tumor N. particularly pyrogenic cancer of the adrenal cortex of clinically manifest symptoms of intoxication (especially fever) may increase the abdomen, sometimes the tumor can be detected by palpation. The clinical picture of hormone-active tumors may resemble the clinical picture of the hormonally-inactive tumors.
Treatment of tumors, usually rapid, malignant tumors, it is combined with chemotherapy. After bilateral adrenalectomy patients need lifelong hormone replacement therapy bark N. After removal of the tumor originating from the cortex NM, another adrenal function may be compromised, so patients are temporarily or even permanently get drugs cortex hormones N. Drug therapy of hormone- activity of the tumor is in wide use hloditana and mammomita.
Treatment of adrenal disease - see adrenogenital syndrome, Virilny syndrome, hyperaldosteronism, Itsenko - Cushing's disease, Itsenko - Cushing's syndrome, etc.
When the diagnosis of diseases and N. appropriate therapy prognosis for life in most patients is favorable, but the disabled have always reduced.
Pathology of the adrenal glands in children has its own peculiarities. The newborn is observed physiological insufficiency of adrenal cortex, which is due to morphological transformation, regression of fetal (embryonic) zone cortex and formation of a permanent structure of the cortical substance, the lack of humoral communication between front part of the pituitary (ACTH production) and the cortical substance.
By N. pathology in children include congenital cortical N. gipoaldosteronizm, chromaffin, Addison's disease, hyperaldosteronism, pituitary - Cushing and others in children with intracranial birth trauma, occurring in severe disease, including