Question

Does drinking Sodium Bicarbonate increase or decrease bowman's capsule pressure (BCP)? Why? How does sodium bicarbonate affect kidney filtration?

Answer 1

• Sodium bicarbonate causes the exchange of H+ into the lumen via the Hydrogen pump and the bicarbonate ion is filtered back to the blood.The high amount of H+ ion create the solute concentration to high in the lumen causing the increase in osmotic pressure in the Bowman capsule. The exchange happens between the tubule cell and the lumen via Na+/H+ pump and the bicarbonate returns via the Na+/Hco3 pump.
• As long the osmotic pressure in the lumen will be increased so the GFR will decrease because for the GFR to be incrased the osmotic pressure should be low in the bowman capsule. As the opposite pressure is high it results in the decrease of the filteration rate. It means the flow towards the lumen decreses as the osmotic pressure is high in the opposite direction due to the higher solute concentration (H+).