Renal transport systems Flashcards
what is the intended effect of diuretics
lower arterial blood pressure by reducing plasma water content
where is the site of action of loop diuretics
loop of Henle (thick ascending limb)
where is the site of action of thiazide diuretics
early distal tubule
where is the site of action of K+ sparing diuretics
late distal tubule
collecting duct
what is the mechanism and binding site of loop diuretics
inhibition of Na+, K+ and Cl- reabsorption
NKCC2 Cl- binding site
what is the mechanism and binding site of thiazide diuretics
inhibition of Na+, Cl- co-transport
NCC Cl- binding site
what is the mechanism and binding site of K+ sparing diuretics
inhibition of Na+ reabsorption and K+ secretion
aldosterone receptor or ENaC
loop diuretics examples
furosemide, bumetanide, torsemide
how do loop diuretics result in the loss of Mg2+ and Ca2+
- K+ is not secreted into the urine
- does not drive ions through the transmembrane space by positive potential
- they are excreted
thiazide diuretics examples
hydrochlorothiazide, chlorothiazide and Bendroflumethiazide
how do thiazides result in reduced Ca2+ excretion
- lowering the sodium concentration in epithelial cells
- the activity of Na+/Ca2+ antiporter is increased
- more Ca2+ is transported into the interstitium
what is the homeostatic mechanism that limits thiazide diuretic effect
- lower blood volume stimulates renin secretion
- leads to aldosterone secretion
- ENaC and Na+/K+ ATPase expression
Aldosterone agonist examples
spironolactone and eplerenone
Na+ channel inhibitor examples
amiloride and triamterene
how do aldosterone agonists reduce K+ secretion
- reduced expression of Na+/K+ ATPase and ENaC
- reduced Na+ reabsorption
- reduced K+ secretion
