SGLT2 Inhibitors, Ketogenesis, and Ketoacidosis

In this study, we will test the hypothesis that distinct mechanisms account for the SGLT2i-induced stimulation of ketogenesis and lipolysis versus endogenous (hepatic) glucose production in patients with type 2 diabetes (T2D) and type 1 diabetes (T1D), and that the increases in ketone production and lipolysis can be prevented by concomitant administration of the thiazolidinedione pioglitazone. We will conduct five distinct experiments to test this hypothesis in patients with T2D and T1D. STUDY 1: To examine the effect of empagliflozin versus empagliflozin/pancreatic clamp on EGP (6,6, D2-glucose), gluconeogenesis (D2O), lipolysis (U-2H-glycerol), ketogenesis (13C-palmitate conversion to 3-betahydroxybuyrate), and norepinephrine turnover (3H-NE) in type 2 diabetes subjects. STUDY 2. To examine the role of the SNS on the empagliflozin-induced stimulation of EGP, lipolysis, and ketone production in T2D by comparing the effect of empagliflozin versus empagliflozin plus propranolol. STUDY 3. To examine the 2-HIT hypothesis that the SGLT2i-induced stimulation of EGP, lipolysis, and ketone production requires the combination of volume depletion plus insulinopenia in T2D individuals. STUDY 4. To examine whether the empagliflozin-induced stimulation of EGP, lipolysis, and ketone production in T2D individuals can be blocked by pioglitazone (which has direct hepatic and adipose tissue effects). STUDY 5. To examine whether the empagliflozin-induced stimulation of EGP, lipolysis, and ketone production in T1D individuals can be blocked by pioglitazone (which has direct hepatic and adipose tissue effects).