Use of Functional MRI to Assess Functional Hypothalamic Activation in Response to Diazoxide

In this study investigators will use functional magnetic resonance imaging (fMRI), a safe, noninvasive method of measuring brain activity by imaging the blood flow to different parts of the brain, to assess the impact of the medication diazoxide on both diabetic and non-diabetic patients. fMRI is a technique for measuring and mapping brain activity. This technique relies on the fact that cerebral blood flow (CBF) and neuronal activity are coupled. Previous rodent and human studies have demonstrated that diazoxide activates potassium (KATP) channels that are sensitive to ATP in the hypothalamus, inhibiting hepatic glucose production. However, these inhibitory effects of diazoxide on hepatic glucose production are curiously absent in diabetic patients, which suggests that they may have impaired activation of KATP channels and thus lowered brain activity in this area of the brain. After screening and meeting eligibility criteria, participants will have 2 day-long study visits (one day in which the brain will be imaged before and after receiving diazoxide, and one day in which the brain will be imaged before and after placebo). Each study day will include up to 3 MRI scans per study visit and hourly blood draws.