In their cavity are the internal carotid artery and cranial nerves, responsible for eye movement and the sensitivity of the face. The membrane of the pituitary gland, called the heart diaphragm, is located 5 mm below the visual intersection - the connection of the optic nerves that occurs behind the eyeballs. The pituitary gland consists of three lobes, two of which, the anterior and middle, are combined into adenohypophysis, and the posterior one is called the neurohypophysis. In each lobe, certain hormones are secreted. The pituitary gland and violation of menstrual function is the topic of the article.
Functions of the pituitary gland
From the adenohypophysis into the bloodstream enter six hormones:
• TSH - thyroid-stimulating hormone.
• ACTH - adrenocorticotron hormone.
• A pair of LH / FSH luteinizing hormone / follicle-stimulating hormone.
• STH is a growth hormone (growth hormone).
• Prolactin.
In the posterior lobe of the pituitary gland, which has a different embryonic origin than the anterior one, two hormones are synthesized:
• ADH - antidiuretic hormone.
• Oxytocin.
The pathology of the pituitary gland can affect the production of one or more hormones, which in a number of cases leads to the development of various diseases. The clinical symptoms of the disease depend on which particular function of the gland is broken.
The main functions of adenohypophysis hormones:
• TSH regulates the secretion of thyroid hormones.
• ACTH controls the activity of the adrenal glands.
• LH and FSH control the function of the sexual glands (ovaries and testes).
• STG regulates growth.
• Prolactin stimulates lactation (milk production) after childbirth.
Hormones of the adenohypophysis fall into the total blood flow and affect certain organs; their secretion is directly regulated by hormones of the hypothalamus and inhibitory hormones. The secretion of pituitary hormones is also controlled by the principle of negative feedback due to themselves and the hormones of those organs to which their action is directed.
The main functions of neurohypophysis hormones:
• Oxytocin controls uterine contractions during labor and milk production during lactation.
• ADH regulates the water-electrolyte balance in the body and affects the kidneys, which allows you to monitor the amount of urine released. Galactorrhea is a process of pathological milk formation in the mammary gland, which is a symptom of prolactin in the secretory tumor of the pituitary gland in women. The most common cause of pituitary dysfunction is adenoma - a benign tumor, which is manifested by an increase or decrease in the synthesis of hormones. The function of the pituitary gland can be disrupted as a result of surgical intervention, radiation therapy, as well as due to degenerative, infectious and inflammatory diseases. However, most often the cause is adenoma (benign tumor) adenohypophysis. This disease can lead to the development of an excess amount of one or more hormones or, on the contrary, cause a slowdown in their synthesis due to a decrease in the activity of the adenohypophysis (hypopituitarism).
Effects of tumors
Tumors of the pituitary gland are relatively rare and are divided into microadenomas (10 mm in diameter or less) or macroadenomas (more than 10 mm in diameter). The disease can be asymptomatic and can be detected during examination for other diseases or after the patient's death. Most often, pituitary tumors are accompanied by headache and progressive deterioration of vision, which is associated with the spread of the tumor to the structures of the visual analyzer. In some cases, blindness may develop. Tumor growth can cause epilepsy, which is associated with pressure and impaired functioning of the cranial nerves. Usually these changes develop gradually. However, if there is a hemorrhage in the tumor tissue at the preclinical stage of development, this can lead to a sharp increase in its size and have catastrophic consequences for the eyesight. During pregnancy, the pituitary gland increases in size, and the symptoms of the tumor can become worse.
Treatment of tumors
The goals of treatment of pituitary tumors: removal of tumors, reduction of pressure on nearby structures and correction of endocrine disorders with preservation, if possible, of normal function of the remaining part of the pituitary gland. Although it is possible to control the secretion of hormones with medications and this also leads to a reduction in tumor size, a radical method of treating the functioning (that is, hormone-producing) pituitary adenoma is an operation using transsphenoidal (through the nose) access and further, if necessary, prevention of relapse. Operative intervention is the method of choice and in the treatment of nonfunctioning tumors, in particular those that are accompanied by a pressure of visual crossover. Vision usually can be restored, especially if treatment is carried out at early stages of the disease. In the presence of large tumors, the surgeon may need another access - through the forehead or parietal area. This operation is called transfrontal craniotomy. A frequent side effect of radiation therapy and surgical treatment is a progressive decrease in the function of the remaining part of the pituitary gland. Such patients should be monitored for life, later they may need hormone replacement therapy.
To diagnose pituitary pathologies, doctors can use various methods of research:
• Blood test. With the help of a blood test, you can determine the level of pituitary hormones and hormones secreted by the endocrine glands, which are affected by the hormones of the pituitary gland. Quantitative assessment of concentrations of ACTH and STH requires a provocative stimulus, for example inulin, induced hypoglycemia (low blood sugar). On the other hand, if there is a suspicion of hypersecretion of ACTH or STH, it is appropriate to conduct a suppression test based on the feedback principle.
• Field of view. Ophthalmologists can precisely establish areas of falling out of fields of vision.
• Radiography. Sometimes a significant change in the Turkish saddle can be detected on the x-ray of the pituitary gland, which indicates the presence of a tumor.
Magnetic Resonance Tomography. Using this method of research, you can obtain accurate images of the area in which the pituitary gland is located and determine the tumor size with high accuracy. Hormones of the pituitary gland play an important role in the regulation of growth and development. Excess or deficiency of one or more hormones can lead to the development of certain diseases.
Growth hormone (OT) is required in children for normal growth, and for adults - to preserve the health of bones, muscles and adipose tissue. The release of STH occurs in portions depending on the effect of hormones of the hypothalamus: somatoliberin, activating the release of STH, and somatostatin, which inhibits this process. The STH is released several times a day; especially intensively it occurs in a dream, and also after such stressful situations for an organism, as reduction of the maintenance of sugar in blood and physical loading. STG has a direct effect on adipose tissue (regulates the breakdown of fats) and muscle; while its effect is opposite to that of insulin. The growth stimulating effect of STH is mediated by a hormone called insulin-like growth factor (IGF-1). It is synthesized in peripheral tissues and liver. The release of STH is regulated by the amount of IGF-1 circulating in the blood on the principle of negative feedback.
Acromegaly
Acromegaly develops if the functioning adenoma of the pituitary gland secretes an excessive amount of STH. This leads to an increase in the mass of soft tissues, as well as an increase in the size of the hands, feet, tongue and the enlargement of the facial features. In addition, patients with acromegaly have increased sweating, hypertension and headache