What is the antidiuretic hormone?

Antidiuretic hormone (also called vasopressin) by the hypothalamus, as the nucleus and paraventricular nucleus of nerve cells secrete the hormone-9, the hypothalamus - pituitary beam after the release of pituitary nerve to reach out. Its main role is to improve the distal convoluted tubule and collecting duct water permeability, and promote the absorption of water, concentrated urine is diluted and the key regulating hormones. Antidiuretic hormone (ADH) Chien-chemical S -------------- S H2N-Gly-Arg-Pro-G-Asn-Gln-Phe-Tyr-G-COOH Antidiuretic hormone (also called vasopressin) by the hypothalamus, as the nucleus and paraventricular nucleus of nerve cells secrete the hormone-9, the hypothalamus - pituitary beam after the release of pituitary nerve to reach out. Its main role is to improve the distal convoluted tubule and collecting duct water permeability, and promote the absorption of water, concentrated urine is diluted and the key regulating hormones. In addition, it Suibu hormone can enhance the collecting duct in the permeability of urea. 1. A major role Change is far tubule epithelial cells and collecting duct water permeability, thus affecting the water re-absorption; loop marrow to increase support or rough section of the NaCl reabsorption and take the initiative in collecting duct Suibu on the permeability of urea, so that Medullary interstitial fluid solute, to increase the concentration of infiltration, conducive to the concentration of urine. 2. Mechanism Antidiuretic hormone and the distal convoluted tubule and collecting duct cell membrane tubes weeks of V2 receptor, activation of the membrane adenosine enzyme so that the epithelial cells in the generation of cAMP increase; cAMP activation of epithelial cells to generate an increase in protein Kinase, protein kinase activation, so that the lumen is located in the vicinity of the membrane channel of water containing vesicles embedded in the membrane lumen, the increase in the luminal membrane of the water channel, thus increasing water permeability. When the lack of antidiuretic hormone, the lumen of the membrane water channels in cell membranes of the clothing focused on depression, which formed pinocytotic vesicles into the cytoplasm, called the shift in (internalization). As a result, the luminal membrane channel water away, the water is not transparent. These channels of water-bearing vesicles embedded in the membrane or lumen from the lumen into the cell membrane, can regulate endometrial luminal water permeability. Basolateral membrane of the water is free through, water through the membrane into the cell lumen after the free-side through the membrane into the capillaries have been re-absorption. Such as: a large number of drinking water, blood, crystal lower osmotic pressure, anti-hormone secretion decreased kidney's reabsorption of water reduction in emission of a large number of low-permeability results of the urine, the body of excess water eliminated from the body, said the phenomenon of the water in urine ( water diuresis). 3. Antidiuretic hormone effects (ADH) release of the factors Regulation of antidiuretic hormone is a major factor in plasma crystals and the cycle of blood pressure, arterial blood pressure. ① osmotic pressure in plasma crystals change could affect the antidiuretic hormone secretion. Sweating a lot. Severe vomiting or diarrhea, and so on the body so that the water loss, increased osmotic pressure in plasma crystals, which can cause increased secretion of antidiuretic hormone, so that the kidney's reabsorption of water activity increased, resulting in concentrated urine and reducing urine volume. On the other hand, a large number of drinking water, the diluted urine, the urine increased, so that the body of excess water eliminated from the body. For example, a healthy drink 100ml of water, about half an hour, began to increase in volume, at the end of the first hour, up to a maximum value of urine; subsequent reduction in urine output, 2-3 hours after the return to the original level of urine . If the drink is isotonic saline (0.9NaCI solution), Pai Niaoliang there is no water to drink after that kind of change. Such a large number of drinking water after the increase in volume, known as the water in urine, which is clinically used to detect kidney diluted the ability of a commonly used test. ② circulating blood volume changes in the reflectivity can affect the release of antidiuretic hormone. Too much blood, the left atrium was expanding capacity to stimulate the receptor, introduced by the vagus nerve impulses into the central and suppress the hypothalamus - pituitary leaves after the release of antidiuretic hormone system, which led to the inappropriate, as a result of the discharge of excess water, normal Blood volume and thus be restored. Reduce blood volume, the opposite occurred. Arterial blood pressure, stimulate the carotid sinus baroreceptor, reflex to inhibit the release of antidiuretic hormone. In addition, atrial natriuretic peptide can inhibit the secretion of antidiuretic hormone, angiotensin Ⅱ can stimulate its secretion.