The part of a nephron in the kidney that leads from the thick ascending limb of the loop of Henle and drains into a collecting duct. The main function of the distal tubule is to ‘fine-tune’ the composition of the filtrate. For example, potassium ions (K⁺) can be either secreted from the distal tubule into the interstitial fluid of the kidney cortex or actively reabsorbed into the tubules, depending on the potassium status of the body fluid. The tubule can also actively transport other ions, such as sodium, chloride, calcium, and hydrogencarbonate ions.