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Hyperkalemia inhibits NH3 synthesis

5.7K views 2 replies 3 participants last post by  signet_ring  
#1 ·
I was reading BRS physiology..it said that Hyperkalemia inhibits NH3 synthesisand the conerse ocurs in hypokalemia..can anyone explain to me how this happens?
Thanks in advance
 
#2 ·
When there is hyperkalemia, there will be increased shift of K+ from the ECF to ICF which is then excreted by the kidneys. To maintain electroneutrality, it will exchange with H+ present in the ICF which can lead to acidemia. This relationship goes both ways. (i.e. acidosis can cause hyperkalemia)
Now to your question, the increased K+ present in the renal tubular cells causes the pH of the cells to increase. The pH of renal tubular cells affects the enzymes involved in glutamine metabolism. An increased pH inhibits the enzymes leading to decreased NH3 formation and thus decreased H+ secretion => acidosis. And a decreased pH stimulates glutamine metabolism leading to increased NH3 formation and increased H+ secretion.
 
#3 ·
When there is hyperkalemia, there will be increased shift of K+ from the ECF to ICF which is then excreted by the kidneys. To maintain electroneutrality, it will exchange with H+ present in the ICF which can lead to acidemia. This relationship goes both ways. (i.e. acidosis can cause hyperkalemia)
Now to your question, the increased K+ present in the renal tubular cells causes the pH of the cells to increase. The pH of renal tubular cells affects the enzymes involved in glutamine metabolism. An increased pH inhibits the enzymes leading to decreased NH3 formation and thus decreased H+ secretion => acidosis. And a decreased pH stimulates glutamine metabolism leading to increased NH3 formation and increased H+ secretion.
shifting of K+ occurs at what side? luminal membrane or basolateral? And can u pls mention what transporters/channels are involved here?