SGLT2 INHIBITION AND STIMULATION OF ENDOGENOUS GLUCOSE PRODUCTION [EGP]: Can the Glucagon-like Peptide-1 [GLP-1] Receptor Agonist, Exenatide, Prevent the Increase in EGP in Response to Dapagliflozin-induced Increase in Glucosuria
SGLT2 INHIBITION AND STIMULATION OF ENDOGENOUS GLUCOSE PRODUCTION [EGP]: Can the Glucagon-like Peptide-1 [GLP-1] Receptor Agonist, Exenatide, Prevent the Increase in EGP in Response to Dapagliflozin-induced Increase in Glucosuria
Research Design/Plan: After screening, each subject will receive 1 measurements of Endogenous Glucose Production [EGP] with prime-continuous Infusion of 3-3H-glucose. After completing the EGP measurement each subject will receive a Double Tracer Oral Glucose Tolerance Test [OGTT].
Methods: Visit 1: Screening. Medical history will be obtained, physical exam performed, and pregnancy test performed.
Visit 2: Endogenous Glucose Production Measurement: The rate of EGP will be measured with 3-3H-glucose.
Visit 3: Double Tracer OGTT
Eligible subjects will receive a measurement of endogenous glucose production (EGP) with a prime-continuous infusion of 3-3H-glucose. The EGP measurement will be performed in the morning after a 10-12 hour overnight fast and will last 8 hours (from 6 AM to 2 PM). After a 3-hour tracer equilibration period, subjects (20 per group) will receive one of the following medications: (i) placebo; (ii) exenatide 5 ug subcutaneously; (iii) dapagliflozin (10 mg); and (iv) dapagliflozin 10 mg plus exenatide 5 ug. Following the test medication at 9 AM, blood samples will be drawn every 15 minutes for an additional 5 hours and plasma glucose, insulin, C-peptide, glucagon, cortisol, growth hormone, and catecholamine concentrations and glucose specific activity will be measured.
Visit 1: Screening. Medical history & physical exam will be performed. Blood will be drawn for fasting plasma glucose [FPG], routine blood chemistries, complete blood count [CBC], lipid profile, HbA1c, and thyroid function [TSH], Urinalysis, electrocardiogram [EKG], albumin/creatinine ratio and pregnancy test will be performed.
Visit 2: EGP Measurement: The rate of endogenous glucose production will be measured with 3-3H-glucose infusion. [3-3H]-glucose infusion will be started at 6 in the morning [AM] and continued until 2:30 afternoon [PM](5 hours after drug administration). At 6 AM a catheter will be placed into an anticubital vein and a prime (40 uCi x FPG/100)- continuous (0.4 uCi) infusion of [3-3H]- glucose will be started and continued until 2:30 PM. (5 hours after drug administration). Participant's hand will be placed in a box heated to 50-60°C (122-140°F). Baseline blood samples will be obtained at-210, -60, -50, -45, -40, -35, -30, -20, -10, and 0 . After 3.5 hours of tracer equilibration blood samples will be obtained every 10-20 minutes from 9 AM to 2 PM. Plasma glucose, insulin, C-peptide, glucagon, cortisol, growth hormone, and catecholamine concentrations, and [3-3H]-glucose specific activity will be measured. Urine will be collected from 6 to 9 AM and from 9 AM to 2 PM. Urinary volume and glucose concentration will be measured and urinary glucose excretion rate calculated. The study will end at 2:30 PM.
Visit 3: Double Tracer Oral Glucose Tolerance Test [OGTT]: Within the week after the measurement of EGP, all subjects will have a 5-hour OGTT with measurement of plasma glucose, insulin (I), C-peptide (CP), and glucagon concentrations at -180, -6-, -5-, -45, -40, -35, -30, -20, -10, 0 and every 15-30 minutes thereafter to obtain a measure of overall glucose tolerance, insulin secretion (CP0-120/G0-120), insulin sensitivity ([Matsuda Index=MI]), beta cell function, (CP0-120/G0-120 x MI), and suppression of plasma glucagon concentration (64). At 7 AM a catheter will be placed into an antecubital vein and a prime (25 uCi x FPG/100)- continuous (0.25 uCi) infusion of [3-3H]- glucose will be started and continued until 3 PM. Urinary volume and glucose concentration will be measured and urinary glucose excretion rate calculated.
HbA1c will be measured 2x, 1 on the day of the OGTT & 1 on the day of the EGP measurement.
Inclusion Criteria:
Exclusion Criteria: