anti-diuretic hormone (ADH)

bedwetting and ADH, can be treated with drugs: desmopresin

normally, ADH elevate during night, increase reabsorption of water, which decrease nocturnal production of urine. However, enuretic children ADH level don't go up at night, so the reabsorption of water don't change and nocturnal production of urine increase

where is it made

1. ADH is made and packaged in hypothalamus 2. vesicles are transported down the hypothalamic-hypophyseal tract to the posterior pituitary 3. ADH is stored in axon terminals in the posterior pituitary 4.ADH is released into the blood when the hypothalamic neurons fires and travels to kidney

what triggers ADH to be release

1. renal reflex: osmolarity of the ECF: cardiovascular system, behavior and kidney 2. changes in blood volume: cardiovascular system, and kidney

mechanism of action of ADH

1.ADH binds to its V2 membrane receptor 2.Receptor binding activates G-protein/cAMP secondary messenger signaling 3. Aquaporin-(AP2) water pores become inserted into the apical membrane via phosphorylation of intracellular proteins 4.Water is transported by AP2 on the *apical surface and by osmosis across the basal membrane into the blood. Water pores are present on basolateral membrane but not regulated by ADH.

ADH functions when the body is dehydrated

1.acts on the kidney: -increases the water reabsorption from the DCT and collecting ducts -increases plasma volume 2.acts to constrict blood vessels: -increases peripheral vascular resistance -increases arterial blood pressure

ADH, (AKA) Arginine vasopressin or vasopressin

ADH regulates the permeability of water in the distal tubule and collecting duct. it acts to increase Aquaporin 2 insert on the apical membrane of distal tubule and collecting duct, allow water to be reabsorbed from the renal tubule.

fluid concentration in the tubule

filtrate entering the distal tubule is hyposmotic. the variable reabsorption of water and solutes in collecting duct is depended on how much ADH is present. more ADH, more condense the urine. Water moved by osmosis out of the lumen to the more concentrated interstitial fluid (ISF)

how does it travel

via vein to kidney

what happens to the concentration of urine its not present (membrane recycling)

• If ADH levels decrease, water pores are removed from the apical membrane by endocytosis • The endocytotic vesicles containing water pores are stored in the cytoplasm until another signal from ADH causes them to be reinserted into the membrane. • This process, in which parts of the cell membrane are alternately added and withdrawn, is known as membrane recycling