Carbonic Anhydrase Mutation Question

[masterofnone101]

How does this work? I understand that with a carbonic anhydrase mutation you basically impair the ability to reabsorb bicarb thus creating metabolic acidosis.

How does this mutation "impair ability of osteoblast to generate acidic environment neccessary for bone resorption" in Osteopetrosis when it creates metabolic ACIDOSIS??

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[chillaxbro]

I think you need a basic environment to build bone not acidic, hence the alkaline phosphatase increases with increased osteoblast activity. And you need acidic environment to resorb bone, hence the the carbonic anhydrase mutation decreases bone resorption

 

[masterofnone101]

But the CA mutation would cause metabolic acidosis - an acidic envioronment right?

 

[dirty630]

Carbonic anhydrase helps the osteoclast create protons for acid. Change the CO2 into H2CO3, then take the H+ off and use that to make the acidic environment to remove bone. Osteoclasts secrete protons to dissolve bone.

Metabolic acidosis from carbonic anhydrase mutations has to do with kidney bicarbonate reabsorption. Metabolic acidosis occurs here because you can't create protons to excrete into urine.

 

[Transposony]

It's LOCAL alkalosis/acidosis for Osteoblast/Osteoclast and not metabolic alkalosis/acidosis.

 

[worldbeater]

Additional point somewhat related to this:
For the patient who is on a mountaintop (they will use a dude who is visiting Peru and is out of breath), the reason a carbonic anhydrase inhibitor works is because it inhibits the bicarb reabsorption into the serum in the PCT, causing a metabolic acidosis. They will cause the patient to have a respiratory alkalosis to even out the pH (normal is 7.35-7.45), and increase his respiratory rate.

Until recently, I kept thinking a patient would be breathing really fast if he was at a high altitude, but it's the opposite, his respirations have slowed down below the normal 12-16 range. The above explanation helped me understand the concept.

 

[hsk013]

so can I think of carbonic anhydrase II mutation (osteopetrosis) as a something similar to an "activating" mutation (instead of inactivating or deletion mutation)?