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SECRETION THE REGULATION HORMONE OF PHYSIOLOGICAL ASPECTS
Mustakimova Ph.A.,
assistant, the Department of Pharmacology and Normal physiology Tashkent Pediatric Medical Institute, Tashkent E-mail: [email protected]
SECRETION THE REGULATION HORMONE OF PHYSIOLOGICAL ASPECTS
Abstract: In the human body, hormones, which are regulated by the neuroendocrine pathway, play an important role, and therefore in our work we examined their regulation on the basis of a literary analysis. Keywords: aspects, physiology, regulation, hormones.
The first level of regulation is realized by the so-called pituitary region of the hypothalamus, which controls the initial (basal) secretion of the anterior lobe of the pituitary gland and neurohypophysis secretion. The second, higher level is provided by other hypothalamic and extrahypothalamic areas of the brain (hippocampus, anterior thalamus, middle brain, etc.) that participate in stimulation or inhibition of pituitary function. Hypogothalamic structures of the brain carry out an important neuroendocrine control of the pituitary gland, and are responsible for the daily rhythm of hormone secretion. The middle brain, hippocampus and anterior medial hypothalamic nucleus participate in the regulation of the secretion ofACTH, gonadotropins, prolactin, growth hormones. In addition, ascending afferent and direct connections of both the reticular formation and the midbrain are projected into the hypothalamus, where dopaminergic and other cells secreting various monoamines are localized.
It is believed that neurotransmitters (monoamines) regulate the pituitary gland by several mechanisms:
a) participation in the synaptic transmission of information coming from the limbic system of the brain to a neuron that produces hypophysitropic hormones (peptides);
b) the effect on the membrane of the hypothalamic neuron and the process of releasing the hypophysitropic hormone;
c) a change in the functional activity of the axon of the hypothalamic neuron in the region of the capillaries of the portal (portal) pituitary system with the modification of the transport of the pituitary hormone to the blood;
d) influence on the cells of the anterior lobe of the pituitary gland with increasing or suppressing their secretory activity or modifying their response to the action of hypophy-sitropic hormones.
The hypothalamus has a rich network ofblood vessels that form a portal system in the mid-elevation region. The most highly vascularized supraoptic and paraventricular nuclei.
Histologically, the region of the middle elevation represents the contact zone containing the endings of numerous neurons localized in these hypothalamic nuclei, through which the secretion products of these neurons (hypophyso-
tropic hormones) reach the capillaries of the portal (portal) pituitary system. Venous capillaries of the portal system have special openings (shunts), which make it possible to transfer compounds with sufficient molecular mass from the blood to the perivascular space of the medial elevation.
The hypothalamus, therefore, is the region that transforms information coming through the nerve pathways from the overlying parts of the nervous system, by changing the level of neurotransmitters (neurotransmitters), which include various monoamines: epinephrine, norepinephrine, dopa-mine, serotonin, acetylcholine, gamma-aminobutyric acid. Stressful situation and other factors lead to a change in the content, rate of synthesis and release of monoamines in the hypothalamus, which in turn, change the rate of secretion of hypothalamic and pituitary hormones, which leads to a corresponding change in the functional activity of the anterior lobe of the pituitary gland.
Thus, the hypothalamus is the place where the nerve and endocrine cells interact with each other, carrying out a fast and highly efficient transmission of information necessary for a quick response from the body, systems and the body as a whole in order to ensure the vital activity of the body. The transfer of information from the cell to the cell is carried out by chemical messengers (hormones and monoamines) and electrical activity. Intercellular interactions, as studies of recent years have shown, can be carried out by the following mechanisms: synaptic messenger transfer; hormonal mechanism through circulating hormones; paracrine mechanism, i.e. without the hormone entering the blood, but only into the intercellular fluid; autocrine mechanism, i.e. the release of the hormone from the cell into the intercellular fluid and the interaction of this hormone with the membrane receptors located on the same cell. It has been shown that norepi-nephrine, somatostatin, dopamine, gonadoliberin, oxytocin, vasopressin can act as hormones and be secreted by endocrine cells or neurons, as well as detected in synapses of nerve cells and serve as neurotransmitters. Another group of hormones -glucagon, enkephalins, cholecystokinin, proiopiomelanocor-tin derivatives, are secreted by endocrine cells, performing hormonal function, and, being localized in the nerve endings,
Medical science
have a neurotransmitter effect. Moreover, these two properties are revealed in other hormones of the adenohypophysis. Ty-roliberin and VIP are secreted by neurons, but they perform a hormonal function, and in the nerve endings they have an obvious neurotransmitter effect.
The effect of the central nervous system on the hypothalamus is not only performed by the above-mentioned nervous mechanisms, but also by the transport of the cerebrospinal fluid of various hormones, neurotransmitters and other substances (endorphins, enkephalins, substance P) that are produced in various areas of the central nervous system and the epiphysis. In the epiphysis, melatonin and a number of other indoles and polypeptides, modulating the function of the adrenal, thyroid and sex glands, are formed. Hormones of the epiphysis are released into the cerebrospinal fluid or the general blood stream and act in various ways. So, mela-tonin concentrates in the hypothalamus and in the middle brain and affects the secretion of hypophysitropic hormones, changing the content of monoamines and neurotransmitters. Other epiphysis polypeptides act directly on the formation of hypophysotropic peptides.
By feedback is meant a system in which the end product of the activity of this system (for example, a hormone, neurotransmitter and other substances) modifies or modifies the function of the components constituting the system aimed at changing the amount of the end product (hormone) or the activity of the system. Vital activity of the whole organism is a consequence of the functioning of numerous self-regulating systems (excretory, cardiovascular, digestive, respiratory and others), which are in turn under the control of the neuroendocrine-immune system. All of the above represents, therefore, a complex of various self-regulating systems that are to a certain extent dependent and
"subordinate". The end result or activity of the system can be modified in two ways, namely by stimulation to increase the amount of the product (hormone) or increase the activity of the effect, or by inhibiting (inhibiting) the system to reduce the end product or activity. The first way of modifying is called positive, and the second-negative feedback. An example ofa positive feedback is an increase in the level of the hormone in the blood, stimulating the release of another hormone (an increase in the level of estradiol in the blood causes the release of LH in the pituitary gland), and negative feedback, when an elevated level of one hormone inhibits the secretion and release of the other (increasing the concentration of thyroid hormones in the blood reduces the secretion of TSH in the pituitary gland).
Hypothalamic-pituitary regulation is carried out by mechanisms functioning on the principle of feedback, in which distinct levels of interaction are clearly distinguished.
By "long" feedback, we mean the interaction of the peripheral endocrine gland with the pituitary and hypothalamic centers (it is possible that both the hypohyposalamic and other areas of the central nervous system) by affecting the indicated centers of the changing concentration of hormones in the circulating blood.
A "short" feedback loop is understood as such an interaction, when an increase in the pituitary tropic hormone (e.g, ACTH) modulates and modifies the secretion and release of the pituitary hormone (in this case, corticoliberin).
Thus, the study of circadian secretion of hormones is of great clinical importance, because with certain diseases (acromegaly, Icenko-Cushing's disease), the violation of the daily rhythm of hormone secretion is an important differential diagnostic feature that is used in the differentiation of syndromi-cally similar pathologies.
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