Distal convoluted tubule
Kidney nephron ("1st proximal convoluted tubule", "2nd distal convoluted tubule")
Section of cortex of human kidney.
Details
Precursor	Metanephrogenic blastema
Identifiers
Latin	tubulus contortus distalis
FMA	17721
Anatomical terminology [edit on Wikidata]

Thedistal convoluted tubule (DCT) is a portion ofkidneynephron between theloop of Henle and thecollecting tubule.

It is partly responsible for the regulation ofpotassium,sodium,calcium, andpH.

On itsapical surface (lumen side), cells of the DCT have athiazide-sensitive Na-Cl cotransporter and arepermeable to Ca, via theTRPV5 channel. On thebasolateral surface (peritubular capillary side) there is an ATP-dependent Na/Kantiporter pump, a secondary active Na/Ca transporter, and anATP dependent Ca transporter. The basolateral ATP dependent Na/K pump produces the gradient for Na to be absorbed from the apical surface via the Na/Clsymporter, and for Ca to be reclaimed into the blood by the Na/Ca basolateral antiporter.

• It regulates pH by absorbingbicarbonate and secretingprotons (H⁺) into the filtrate, or by absorbingprotons and secretingbicarbonate into the filtrate.
• Sodium and potassium levels are controlled by secreting K⁺ and absorbing Na⁺. Sodium absorption by the distal tubule is mediated by thehormonealdosterone. Aldosterone increases sodium reabsorption. Sodium and chloride (salt) reabsorption is also mediated by a group of kinases called WNK kinases. There are 4 different WNK kinases,WNK1,WNK2,WNK3, andWNK4.
• It also participates incalcium regulation by reabsorbing Ca²⁺ in response to parathyroid hormone.^[1] PTH effect is mediated through phosphorylation of regulatory proteins and enhancing the synthesis of all transporters within the distal convoluted tubule.
• Arginine vasopressin receptor 2 is also expressed in the DCT.

Thiazidediuretics inhibit Na⁺/Cl⁻ reabsorption from the DCT by blocking thethiazide-sensitive Na-Cl cotransporter.

By inhibiting the transporter, thiazide diuretics increase the gradient potential for Na. This increases the activity of the basolateral Na/Ca antiport and causes the increase in calcium reclamation associated with thiazide diuretics.

The DCT is lined with simple cuboidal cells, thedistal convoluted tubule cells, that are shorter than those of theproximal convoluted tubule (PCT). The lumen appears larger in the PCT than the DCT lumen because the PCT has a brush border (microvilli). DCT can be recognized by its numerousmitochondria (even though it is not as much as PCT), basal enfoldings and lateral membrane interdigitations with neighboring cells.

The point where DCT contacts thecortical thick ascending limb of theloop of Henle is calledmacula densa. It has tightly packed columnar cells which display reversed polarity and may monitor the osmolarity of blood.

Histologically, cells of the DCT can be differentiated from cells of theproximal convoluted tubule:

• 
  1Glomerulus, 2proximal tubule, 3 distal tubule
• 
  Transverse section of pyramidal substance of kidney of pig, the bloodvessels of which are injected.
• 
  Renal corpuscle
• 
  Diagram outlining movement of ions in nephron.

List of distinct cell types in the adult human body

• Histology image: 16004loa – Histology Learning System at Boston University
• Histology image: 16007loa – Histology Learning System at Boston University

• Kidney anatomy

• Articles with short description
• Short description is different from Wikidata