SGLT2 is located in the S1 segment of proximal renal tubule and is a high-capacity, low-affinity transporter that mediates the majority of the glucose reabsorption. Glucose which escapes SGLT2 is reabsorbed by SGLT1, a low-capacity, high-affinity transporter located in the S3 segment of the proximal renal tubule. Under conditions where SGLT2 is inactivated by either a mutation or an inhibitor, urinary glucose excretion can range from 20-200 g/day or more.