Distal Convoluted Tubule (DCT): Conditional reabsorption of Na and water takes place in this segment. DCT is also capable of reabsorption of HCO3– and selective secretion of hydrogen and potassium ions and NH3 to maintain the pH and sodium-potassium balance in blood. Human urine is usually acidic because hydrogen ions are actively secreted into the filterate. Reabsorption of water from distal parts of the renal tubule is facilitated by hormone ADH. Glycosuria and Ketonouria in Urine are indicative of Diabetes mellitus.