The distal convoluted tubule of the nephron is the part of the kidney between the loop of henle and the collecting duct. When renin is released from the kidneys, it causes the activation of angiotensin I in the blood circulation which is cleaved to become angiotensin II. Angiotensin II stimulates the release of aldosterone from the adrenal cortex and release of vasopressin from the posterior pituitary gland. When in the circulation, vasopressin eventually binds to receptors on epithelial cells in the distal convoluted tubule. This causes vesicles that contain aquaporins to fuse with the plasma membrane. Aquaporins are proteins that act as water channels once they have bound to the plasma membrane. As a result, the permeability of the distal convoluted tubule changes to allow for water reabsorption back into the blood circulation. In addition, sodium, chlorine, and calcium are also reabsorbed back into the systemic circulation via their respective channels and exchangers. However, aldosterone is a major regulator of the reabsorption of these ions as well, as it changes the permeability of the distal convoluted tubule to these ions. As a result, a high concentration of sodium, chlorine, and calcium in the blood vessels occurs. The reabsorption of ions and water increases blood fluid volume and blood pressure.

Kidney Function - Distal Convoluted Tubule References