An increase in NaCl and water content also mean that protein is more dilute and therefore oncotic pressure falls. Sodium reabsorption is the key to several co-transport systems in the PCT for the reabsorption of glucose, amino acids, phosphate, calcium and bicarbonate, and for the secretion of hydrogen ions. Sweet urine, osmotic diuresis, dehydration and thirst. Passive entry of Na down its electrochemical gradient permits entry of glucose against its gradient. Passive Na gradient maintained by active extrusion from peritubular side by Na pump.
Parathormone reduces reabsorption, ie more lost in urine.
See Computer tutorial.