ADH & Diuretics - Trachte

Question 1

What is the mechanism of ADH?

Answer 1

• Stimulate G-protein coupled receptor (Gs) in collecting duct
• Upregulate cAMP
• Recruit aquaporin channels to incorporate into luminal plasma membrane
  
  • water moves by osmosis and gets reabsorbed in peritubular capillaries

Question 2

What effect does ADH have on urine flow?

Answer 2

Decreased urine flow

(ANTI-diuretic hormone => decreased diuresis)

Question 3

What effect does ADH have on ion concentrations?

Answer 3

• Decreased [ion] in blood/serum
• Increased [ion] in urine

Question 4

Where do loop diuretics act in the nephron?

Answer 4

thick ascending limb

Question 5

Where do thiazide diuretics act in the nephron?

Answer 5

distal convoluted tubule

Question 6

Where do potassium-sparing diuretics act in the nephron?

Answer 6

collecting duct

Question 7

Where do osmotic diuretics act in the nephron?

Answer 7

proximal tubule and/or descending limb of the loop of Henle

Question 8

Where do Sodium-Glucose Transport Inhibitors (SGLT-2) act in the nephron?

Answer 8

Proximal tubule

Question 9

Where do carbonic anhydrase inhibitors act in the neprhon?

Answer 9

proximal tubule

Question 10

What diuretic(s) inhibits the Na, K, 2Cl pump in the thick ascending limb of the loop of Henle?

Answer 10

Furosemide (Lasix) and Bumetanide

Question 11

What is the influence of Furosemide (Lasix) & Bumetanide on urine flow and ion concentrations in the urine?

Answer 11

• Prevent decrease in osmolarity
  
  • results in greater retention of ions and water in later segments of the nephron
• Increase NaCl excretion
• Increase K⁺ excretion

Question 12

What diuretics block the NaCl transporter in the distal convoluted tubule?

Answer 12

• Chlorthalidone
• Hydrochlorothiazide
• Metalazone

Question 13

What is the influence of HCTZ, Chlorthalidone, & Metalazone on urine flow and ion concentrations in the urine?

Answer 13

• Increased excretion of water, Na⁺, Cl^-, and K⁺ in the urine
  
  • K⁺ gets excreted because some of the increased Na⁺ is exchanged for K⁺ in the collecting tubule

Question 14

What diuretics inhibit aldosterone receptors in the collecting duct?

Answer 14

Spironolactone & Eplerenone

Question 15

What diuretics inhibit the Na⁺ exchange (ENaC) for K⁺ and H⁺ in the collecting duct?

Answer 15

Amiloride & Triamterene

Question 16

What is the influence of Spironolactone, Amiloride, & Triamterene on urine flow and ion concentrations in the urine?

Answer 16

• Less potassium is excreted
  
  • due to blocking the exchange of intraluminal Na⁺ for extraluminal K⁺ in collecting duct

Question 17

What type of diuretic is Mannitol?

Answer 17

Osmotic diuretic

Question 18

What diuretic blocks the Na⁺/Glucose symporter in the proximal tubule?

Answer 18

Canigliflozin, Dapagliflozin, Gliflozin

(–flozin)

Question 19

What diuretic is a major carbonic anhydrase inhibitor?

Answer 19

Acetazolamide

Question 20

What is the influence of Acetazolamide on urine flow and ion concentrations in the urine?

Answer 20

• Urinary alkalinization
• Produces metabolic acidosis

Question 21

What is the major side effect of thiazide diuretics?

Answer 21

• Hyperglycemia
  
  • thiazides bind SUR on potassium channels that control insulin release
  • opens potassium channels
  • K⁺ influx => hyperpolarizes ß-cells in pancreas
    
    • results in suppressed insulin release!

***Also predisposes pts. to gout.

Question 22

What is the influence of Mannitol on urine flow and ion concentrations in the urine?

Answer 22

• Reduced water reabsorption
  
  • increased urine flow
  • decreased [ion]

Question 23

What are the drugs suppress uric acid reabsorption by blocking organic anion transporters (OAT) and URAT1 in the proximal tubule?

Answer 23

Probenicid & Sulfinpyrazone

Question 24

What is the name of the naturally occurring hormone that is antidiuretic?

Answer 24

Vasopressin

Question 25

What is the name of the synthetic cogener of ADH?

Answer 25

Desmopressin