distal convoluted tubule

Last reviewed 07/2021

The volume of fluid reaching the distal convolute tubule:

  • is only 20% of the glomerular filtrate
  • has only 10% of filtered sodium remaining

The tubular fluid entering the DCT is hypotonic because of the active pumping occurring in the ascending limb of the loop of Henle.

This residual sodium is reabsorbed under the control of aldosterone.

Increased aldosterone causes:

  • reabsorption of the sodium in the DCT
  • secretion of potassium and hydrogen ions into the DCT

The hydrogen ions are primarily buffered by secreted ammonia.