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ACTH (Adrenocorticotropic Hormone )

ACTH - peptide hormone secreted by the anterior pituitary gland under the influence of tropic hormones of the hypothalamus ( corticotropin-releasing hormone), consists of 39 amino acid residues with a molecular weight of 4,500 Da. Half-life in the blood - 3-8 minutes. Its transformation occurs mainly in the liver and in a small number - in the kidneys. To a greater extent, its influence is expressed on the bundle zone of the adrenal cortex, which leads to an increase in the formation of glucocorticoids, in less - to the glomerular and reticular zones, so it does not have a significant effect on the production of mineralocorticoids and sex hormones. Vnenadococcal effects of ACTH are to stimulate lipolysis (mobilizes fats from fat stores and promotes fat oxidation), increased secretion of insulin and growth hormone, accumulation of glycogen in muscle cells, hypoglycemia, which is associated with increased secretion of insulin, increased pigmentation due to the effect on pigment cells of melanophores . The secretion of ACTH increases with stress, as well as under the influence of factors, causing stressful conditions: cold, pain, physical activity, emotions. Hypoglycaemia increases the production of ACTH. Deceleration of ACTH production occurs under the influence of glucocorticoids themselves. Excess ACTH leads to hypercortisy. This disease develops with the adenoma of the pituitary gland and is called the diseaseItenko-Cushing . The main manifestations of the disease - hypertension, obesity, having a local character (face and body), hyperglycemia, decreased immune defenses of the body. Lack of a hormone leads to a decrease in the production of glucocorticoids and the development of hypocorticism, which is manifested by a violation of metabolism and a decrease in the body's resistance to various environmental influences. Secretion of ACTH in the blood is subject to daily rhythms - the concentration is maximal at 6 am, minimal in the evening and at night (about 22 hours). The normal daily rhythm of hormones testifies to the integrity of the functioning of all links of the system " hypothalamus-pituitary- adrenal cortex".