Effect of Chronic ACE and DPP4 Inhibition on Blood Pressure

"Subjects will receive two capsules of placebo to preserve the blinding of the study.~In a separate period, subjects will receive one capsule of placebo and one capsule of sitagliptin."

Subjects will receive sitagliptin 100mg daily for 7 days. In addition, subjects will receive either aprepitant or a capsule of placebo to preserve the blinding of the study.

Subjects will receive aprepitant (125 mg on the first day followed by 80mg/d) for 7 days along with sitagliptin.

The first 18 subjects per arm/ group will undergo a mixed meal test on the 7th day of each medication intervention. This will take place after the first half of the study day at the clinical research center, following a 30 minute rest. Subjects will ingest a shake (combination of fixed carbohydrates/ fat/ protein) and have blood pressure, heart rate, and venous blood sample measurements collected for 4 hours after the meal.