Paradoxical Stimulation of Hepatic Glucose Production With Dapagliflozin

The University of Texas Health Science Center at San Antonio30 enrolled

Overview

To determine the role of plasma glucagon and insulin in the rise of endogenous glucose production (EGP) following the SGLT2 inhibition.

The increase in plasma glucagon conc and/or decrease in plasma insulin conc in response to glucosuria is (are) important signal(s) responsible, at least in part, for the increase in EGP, which the investigators anticipate will be derived primarily from the liver. Insulin and glucagon are powerful regulators of HGP. Therefore, the investigators anticipate that, at least in part, an increase in HGP secondary to the rise in plasma glucagon concentration and decrease in plasma insulin concentration in response to dapagliflozin-induced glucosuria will account for the majority of increase in EGP in both NGT and T2DM subjects. This study will define whether the increase in plasma glucagon and/or the decrease in plasma insulin are the trigger to stimulate EGP. Eligible subjects will receive three 5-hour measurements of endogenous glucose production (EGP), which is the biosynthesis of new glucose, with administration of study drug after a 3-hour tracer equilibration period. Hepatic glucose production (HGP), which is the net release of glucose from the liver, will be measured for 5 hours after drug administration to allow sufficient time for a significant increase in HGP above baseline after dapagliflozin administration (10). In study 1, HGP will be measured for 5 hours after dapagliflozin (10 mg) or placebo administration. This is the control study. The investigators expect to observe the "paradoxical" rise in EGP following dapagliflozin. Study 2 will be performed under glucose clamp conditions (i.e. maintaining the plasma glucose concentration stable at each subject's fasting level). This study will define whether the decline in plasma glucose concentration is the trigger to stimulate EGP. Study 3 will be performed under pancreatic clamp conditions (maintaining the plasma glucagon and insulin concentrations constant at the basal level). This study will define whether the increase in plasma glucagon and/or the decrease in plasma insulin are the trigger to stimulate EGP. Subjects will be randomized in a 2:1 ratio; 32 subjects will receive dapagliflozin and 16 subjects will receive placebo. Each study will be performed on a separate day, after a 10-12 hour overnight fast within 1-2 week period. Following studies 1-3, subjects will return for a renal (kidney) MRI-measurement to record kidney size.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Type II; Diabetes

Interventions

DapagliflozinDRUG

Three 5-hour measurements (after dapagliflozin 10mg administration) of endogenous glucose production (EGP) will be performed on separate days.

PlaceboDRUG

Three 5-hour measurements (after placebo administration) of endogenous glucose production (EGP) will be performed on separate days.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * T2DM according to ADA criteria-HbA1C \< 8.0% * BMI = 25-35 kg/m2 * Subjects must be in good general health as determined by physical exam, medical history, blood chemistries, CBC, TSH, T4, EKG and urinanalysis * Body weight has been stable (± 3 lbs) over the preceding three months * Do not participate in an excessively heavy exercise program * Taking stable dose (more than 3 months) of monotherapy or combination therapy with metformin and/or a sulfonylurea Exclusion Criteria: * Subjects taking drugs known to affect glucose metabolism (other than metformin and sulfonylurea) will be excluded * Individuals with evidence of proliferative diabetic retinopathy, plasma creatinine \>1.4 females or \>1.5 males, or 24-hour urine albumin excretion \> 300 mg will be excluded

Locations (1)

University of Texas Health Science Center

San Antonio, Texas, United States

Outcomes

Primary Outcomes

Measurement of the Change in Plasma Glucose (mg/dL): Study 1

Change from baseline to the last hour of the study (240-300 minutes) in plasma glucose concentration

Time frame: Baseline to 240-300 minutes

Change in Plasma Glucose Measurement Using a Glucose Clamp: Study 2

Change from baseline to the last hour of the study (240-300 minutes) in plasma glucose for study 2: EGP plus glucose clamp. The glucose clamp technique is achieved by increase plasma glucose concentration to 125 mg/dl above basal levels by a continuous infusion of glucose. This hyperglycemic plateau is maintained by adjustment of a variable glucose infusion, based on the rate of insulin secretion and glucose metabolism. Because the plasma glucose concentration is held constant, the glucose infusion rate is an index of insulin secretion and glucose metabolism. The 3-3H-glucose infusion will be started at 6 AM to measure the basal rate of EGP. After a 3 hour tracer equilibration period (at 9 AM) subjects will receive dapagliflozin (10 mg) or placebo, and the plasma glucose conc will be measured every 5 minutes for 5 hours (from 9AM to 2 PM)

Time frame: Baseline to 240-300 minutes

Change in Plasma Glucose Using a Pancreatic Clamp: Study 3

Change from Baseline to the last hour of the study (240-300 minutes) in plasma glucose using a pancreatic clamp. In this study, EGP will be measured as described in Study 1 and plasma insulin and glucagon concentrations will be clamped at the basal level using the pancreatic clamp technique. Plasma glucose concentration will be allowed to decrease spontaneously after dapagliflozin or placebo administration. Somastatin will be infused with glucagon and insulin to replace basal plasma glucagon and insulin until study end.

Time frame: Baseline to 240-300 minutes

Change in EGP: Study 1

Change from baseline to the last hour of the study (240-300 minutes) in EGP

Time frame: Baseline to 240-300 minutes

Change in EGP With Glucose Clamp: Study 2

Data from ClinicalTrials.gov

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Secondary Outcomes

Change in Plasma Insulin Concentrations: Study 1

Plasma insulin concentrations during measurement of EGP

Time frame: Baseline to 240-300 minutes

Plasma Insulin Concentrations During Measurement of EGP Plus Glucose Clamp: Study 2

Plasma insulin concentration is measured from baseline to the last hour of the study while using a glucose clamp. The glucose clamp technique is achieved by increase plasma glucose concentration to 125 mg/dl above basal levels by a continuous infusion of glucose. This hyperglycemic plateau is maintained by adjustment of a variable glucose infusion, based on the rate of insulin secretion and glucose metabolism. Because the plasma glucose concentration is held constant, the glucose infusion rate is an index of insulin secretion and glucose metabolism. The 3-3H-glucose infusion will be started at 6 AM to measure the basal rate of EGP. After a 3 hour tracer equilibration period (at 9 AM) subjects will receive dapagliflozin (10 mg) or placebo, and the plasma glucose conc will be measured every 5 minutes for 5 hours (from 9AM to 2 PM)

Time frame: Baseline to 240-300 minutes

Change in Plasma Insulin While Using Pancreatic Clamp: Study 3

Plasma insulin concentration during measurement of EGP while using pancreatic clamp. In this study, EGP will be measured as described in Study 1 and plasma insulin and glucagon concentrations will be clamped at the basal level using the pancreatic clamp technique. Plasma glucose concentration will be allowed to decrease spontaneously after dapagliflozin or placebo administration. Somastatin will be infused with glucagon and insulin to replace basal plasma glucagon and insulin until study end.

Time frame: Baseline to last hour of the study

Change in Glucagon: Study 1

Change in glucagon concentrations during measurement of EGP

Time frame: Baseline to 240-300 minutes

Change in Glucagon Using Glucose Clamp: Study 2

Plasma glucagon concentration during measurement of EGP using a glucose clamp. The glucose clamp technique is achieved by increase plasma glucose concentration to 125 mg/dl above basal levels by a continuous infusion of glucose. This hyperglycemic plateau is maintained by adjustment of a variable glucose infusion, based on the rate of insulin secretion and glucose metabolism. Because the plasma glucose concentration is held constant, the glucose infusion rate is an index of insulin secretion and glucose metabolism.

Time frame: Baseline to 240-300 minutes

Change in Glucagon Using Pancreatic Clamp: Study 3

Measurement of change in plasma glucagon from baseline to one hour prior to end of study while using a pancreatic clamp. In this study, EGP will be measured as described in Study 1 and plasma insulin and glucagon concentrations will be clamped at the basal level using the pancreatic clamp technique. Plasma glucose concentration will be allowed to decrease spontaneously after dapagliflozin or placebo administration. Somastatin will be infused with glucagon and insulin to replace basal plasma glucagon and insulin until study end.

Time frame: Baseline to 240-300 minutes