Essentials of SGLT2 Inhibitors in Diabetes
2. SGLT2 Inhibitors for Treating Diabetes
Sodium-glucose cotransporter-2 (SGLT2) inhibitors have a novel therapeutic action compared with the many drugs available to the prescriber to treat type 2 diabetes. The pharmacological action of this drug class is in the kidneys, which play an important role in glucose homeostasis by filtering and reabsorbing glucose in the proximal tubules. On a daily basis, the kidney filters approximately 180 g of glucose. The majority of filtered plasma glucose (80–90 %) is reabsorbed in the early proximal tubule by the high capacity, low affinity SGLT2 . The other 10–20 % is reabsorbed by the low capacity but high-affinity SGLT1 in the more distal portion of the proximal tubule (Fig. 2.1) . This is achieved by cotransporting glucose with sodium via Na +/K +–adenosine triphosphatase pumps. SGLT2 is selectively expressed in the kidney, whereas SGLT1 is also expressed in the gastrointestinal tract where it has a role in the absorption of glucose and galactose . In healthy individuals, virtually all glucose is reabsorbed and the urine is free from glucose.