In the sodium-glucose symporter, sodium moves down its concentration gradient to move glucose up its concentration gradient. Sodium has a greater concentration outside of the cell, and binds to the symporter, which is in its outward facing conformation. Once sodium is bound, glucose can bind from the extracellular space, causing the symporter to switch into the occluded formation (closed) before opening to the inside of the cell and releasing the two sodium ions and the one glucose molecule. Once both are released, the symporter re-orients itself to the outward facing conformation and the process starts all over again. A major example of up-regulation of the sodium-glucose symporter is seen in patients with type 2 diabetes, where there is roughly a 3-4 fold up-regulation of the sodium-glucose symporter (SGLT1). This leads to an influx of glucose into the cell and results in hyperglycemia.