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 potassium secretion and PH  



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Author7 Posts
  #1

could any one explain how k secretion changes during acidosis(chronic/acute) and alkalosis(chronmic/acute),please!
i have looked in several postes here but no one gave me the accurate answer with rigth explanation(firtst time same question has been posted in 2005 and still seems not solved!)

for example,i know in acidosis H goes in cell and K out ,,,,so how come k secretion decrease? b/c we have hyperkalemia and hyperkalemia induce Aldosterone secretion and that would lead to increase K secretion...
please if any one knows let us know
thank you




  #2

In acidosis, kidney tries to compensate by sending HCO3- to blood and in
exchange sends H+ to urine...this H+ will neutralize the negative charge on
the luminal membrane, this in turn will attract less K+ there and thus K+ secretion will decrease...




  #3

Now for DETAILS

ACUTE ALKALOSIS:::
H+ has to move out of the cells into the plasma which in turn will shift K+ into the cell leading to hypokalemia( while intracellular K will be elevated)
renal excretion ( secretion) of K+ will increase however bc of alkalosis kidney will pump less HCO3- to the blood n thus less H+ in urine. the negative charge on luminal membrane will be strongly attracting K+ since H+ was less here.
result...>negative potassium balance

CHRONIC ALKALOSIS:::
exactly the same as above
only difference is that intracellular K+ are also decreased, reason being bc body gets potassium depleted after 24 hrs of the above mentioned scenario of negative potassium balance


  #4

sireen wrote:
Now for DETAILS

ACUTE ALKALOSIS:::
H+ has to move out of the cells into the plasma which in turn will shift K+ into the cell leading to hypokalemia( while intracellular K will be elevated)
renal excretion ( secretion) of K+ will increase however bc of alkalosis kidney will pump less HCO3- to the blood n thus less H+ in urine. the negative charge on luminal membrane will be strongly attracting K+ since H+ was less here.
result...>negative potassium balance

CHRONIC ALKALOSIS:::
exactly the same as above
only difference is that intracellular K+ are also decreased, reason being bc body gets potassium depleted after 24 hrs of the above mentioned scenario of negative potassium balance

ok i understand what you say,my problem is about ald and k.. now you tell me,please ;?
hyperkalmeia increase ald.rigth?so hypokalemia should decrease ald .less ald means less sodium reabsorption.right?
mow less Na reabsorption make lumen less negatuive therefore less K attracted into lumen (K secretion decreased)


  #5

i mean the lumen charge is not only due to H but also Na so although H secretion decreases in alkalosis but also Na reabsoroption decreases,,,

maybe H has a bigger role here???confused

thanks for your answer


  #6

U do have a point, some other friend on this forum should help coz i cant figure it out.
in the meanwhile if i do come up with an answer for aldosterone in this situation i will be more than pleased to let u know smiling face


  #7

sireen thanks for your time and trying to help me heresmiling face

i hope some one can provide the answer ,,and if you could i would be so happysmiling face







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