PROTOCOL 3: Role of the Renal Nerves in the Increase in EGP in Response to Glucosuria

Purpose/Objectives: Examining the effect of SGLT2 inhibition on EGP and plasma glucose concentration in diabetic and non-diabetic subjects after kidney transplantation (i.e. renal denervation) or in subjects after renal sympathectomy (63) can add insight about the possible role of a neural arc which mediates the changes in plasma glucagon and/or insulin concentration in response to glucosuria.

Research Design/Plan: After screening, eligible subjects will receive 2 measurements of endogenous glucose production with a prime-continuous infusion of 3-3H-glucose. Each measurement will be performed on a separate day in random order 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, each subject will receive one of the following medications in random order: (i) placebo and (ii) dapagliflozin 10 mg. Following the test medication at 9 AM, blood samples will be drawn every 20 minutes for an additional 5 hours and plasma glucose, insulin, C-peptide, glucagon, catecholamine concentrations and tritiated glucose sp act will be measured.

Methods: Visit 1: Screening Visit 2: Endogenous Glucose Production Measurement (EGP) Visit 3: After completing the first EGP measurement, subjects will return to the Diabetes Research Unit for the second study.

Inclusion criteria

• age = 18-70 years
• BMI = 18.5-40 kg/m2
• HbA1c ≥ 7.0% and ≤10.0% for type 2 diabetics
• males or females
• Must be at least 3 months post renal transplantation and be on a stable dose of prednisone (≤5 mg/day), tacrolimus, and mycophenolate mofetil
• Not taking any antidiabetic medications or who are treated with metformin, sulfonylurea, dipeptidyl peptidase 4 (DPP4) inhibitor, thiazolidinedione or some combination
• Must be in good general health as determined by physical exam, medical history, blood chemistries, CBC, TSH, T4, EKG and urinanalysis

Exclusion criteria

• Subjects who are taking insulin or SGLT2 inhibitor are excluded
• Only subjects whose body weight has not been stable (± 3 lbs) over the preceding three months and/or who participate in an excessively heavy exercise program will be excluded.
• Individuals with evidence of proliferative diabetic retinopathy, plasma creatinine >1.4 females or >1.5 males (and eGFR <45ml/min.1.73m2), or 24-hour urine albumin excretion > 300 mg will be excluded.