54-LB: Distinct Mechanisms Are Responsible for the Increase in Endogenous Glucose Production and Ketone Formation following Empagliflozin in T2DM Patients

Aim: To examine the mechanisms responsible for the increase in glucose and ketone production caused by SGLT2 inhibition with empagliflozin in T2DM patients. Research Design and Methods: 12 T2DM subjects (Age = 53; BMI = 31.7; HbA1c = 7.4%) participated in two studies performed in random order. At 0700h following an overnight fast subjects received an 8-hour infusion of 6,6D2-glucose to measure endogenous (hepatic) glucose production. At 0900 h an infusion of 3H-norepinephrine was started. At 1000h subjects ingested 25 mg of empagliflozin (n=8) or matching placebo (n=4) and were followed for 5 hours (1500 h) . Within 1 week subjects returned for a repeat study with pancreatic clamp to maintain plasma insulin and glucagon concentrations constant at the basal level. As per study one, subjects ingested empagliflozin 25 mg or placebo prior to the pancreatic clamp. Results: When empagliflozin was ingested under fasting conditions, EGP increased by 31% in association with a decrease in plasma glucose (-34 mg/dl) and insulin (-52%) concentrations and increases in plasma glucagon (+19%) , FFA (+29%) and β-hydroxybutyrate (β-HB) (+48%) concentrations. When empagliflozin was ingested under pancreatic clamp conditions, plasma insulin and glucagon concentrations remained unchanged, and the increase in plasma FFA and ketone concentrations was completely blocked, while the increase in EGP persisted. Total-body NE turnover rate increased significantly in subjects receiving empagliflozin (+67%) compared to placebo under both fasting and pancreatic clamp conditions. No difference in plasma norepinephrine concentration was observed in either study. Conclusion: The decrease in plasma insulin and increase in plasma glucagon concentration caused by empagliflozin is responsible for the increase in plasma FFA concentration and ketone production. The increase in EGP caused by empagliflozin is independent of the change in plasma insulin or glucagon concentrations and is explained by the increase in total-body NE turnover.