Glucose dynamics and mechanistic implications of SGLT2 inhibitors in animals and humans

Glucose is freely filtered in the glomeruli before being almost entirely reabsorbed into circulation from the proximal renal tubules. The sodium-glucose cotransporter 2 (SGLT2), present in the S1 segment of the proximal tubule, is responsible for the majority of glucose reabsorption. SGLT2 inhibitors reduce glucose reabsorption and increase urinary glucose excretion. In animal models and humans with type 2 diabetes, this effect is associated with reduced fasting and postprandial blood glucose levels, and reduced hemoglobin A1c. Animal studies suggest that reduction of hyperglycemia with SGLT2 inhibitors may also improve insulin sensitivity and preserve β-cell function. Urinary excretion of excess calories with SGLT2 inhibitors is also associated with reduction in body weight. Modest reductions in blood pressure have been noted with SGLT2 inhibitors, consistent with a mild diuretic action. Some C-glucoside SGLT2 inhibitors, such as dapagliflozin, have pharmacokinetic properties that make them amenable to once-daily dosing.