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19 Cards in this Set
- Front
- Back
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What are the 3 parts of the ADH precursor protein? Where is this found?
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A) ADH. B) Neurophysin. C) glycoprotein w/ unknown function. Posterior pituitary
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What 4 things increase ADH secretion?
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1) Elevated serum osmolality (dehydration -> Na). 2) dec in extracellular volume from bleeding or dehydration. 3) AT2. 4) CLOFIBRATE
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V1 receptors do what? Location of V1a and V1b?
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1) Cause an increase in PIP hydrolysis. V1a is located in vascular smooth muscle and brain. V1b is located in pituitary.
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Location of V2 receptors? Function?
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On apical surface of tubular cells of collecting ducts and DCT (V2 like receptors found on endothelial cells). Inc intracellular cAMP -> regulates aquaporins and urea transport
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AQP2 located where?
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Inside vesicles
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What does phosphorylation do in regards to AQP2?
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causes vesicles to fuse with apical surface, translocation of AQP2
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ADH effects on 1) blood vessels? 2) H2O permability? 3) renal blood flow?
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1) potent vasoconstrictor, esp at [higher] due to V1 receptors. 2) inc permeability in tubules (V2 receptors) -> greater water retention. 3) dec inner medullary blod flow (V1a receptor) allows enhanced concentrating capacity
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ADH effects on 4) thirst/appetite? 5) ACTH? 6) coagulation factors?
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4) inc thirst and salt appetite. 5) inc ACTH release. 6) INCREASED PRODUCTION OF COAGULATION FACTOR VIII
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Diabetes Insipidus. List 2 taught causes, mechanism, and Tx.
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1) Central or Neurogenic (most common). Lack of ADH production in posterior pituitary. Tx w/ desmopressin. 2) Nephrogenic. Mutation in ADH V2 receptors or AQP2. Make a lot but never reaches apical surface. Tx w/ thiazide diuretic which somehow dec urine production.
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Do individuals w/ mutations in AQP2 get facial flushing? Why?
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b/c V2 receptors exist elsewhere, individuals w/ mutations in AQP2 get facial flushing but DI pts with V2 receptors mutations would not.
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What is desmopressin? Used for what?
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Vasopressin agonist. Used for 1) DI. 2) specific GI bleeds (not duodenal or gastric ulcers). 3) some colonic diverticulm
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Desmopressin duration? Receptor affinity? Implication of this?
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long duration (14-20hrs) -> once a day dosing. 2000x affinity for V2 receptors -> little vasoconstrictor activity
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List 2 drug interactions of desmopressin.
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1) clofibrate increases section of water then…. 2) chlorpropamide increases action of ADH
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Vasopressin has what duration?
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short acting
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Lysine Vasopressin has what quality?
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more stable analogue
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Demecloclycline is what and used for what?
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vasopressin antagonist (tetracycline derivative) used for inappropriate secretion
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How does demecloclycline work?
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Interferes with the increase of water permeability caused by ADH. Does not interfere with production of cAMP
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In regards to ADH, what is Lithium and what is it used for?
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Vasopressing antagonist used for inappropriate ADH secretion
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How does lithium work?
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Antagonizes ADH mediated increases in cAMP. Possibly by decreasing insertion of vesicles
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