Determination of Beta-cell Responsiveness to the Incretin Hormones GLP-1 and GIP in Cystic Fibrosis
In recent years, diabetes has emerged as one of the most significant co-diseases that many Cystic Fibrosis (CF) patients develop. Type 1 (T1D) and Type 2 (T2D) diabetes results when either the body does not make enough insulin or the body does not respond correctly to this insulin, respectively. Insulin is a hormone which is made by cells in the pancreas and helps carry glucose (sugar) from the food we eat to the cells of the body for energy. While cystic fibrosis related diabetes (CFRD) has many features similar to both T1D and T2D, patients with CF may not have the same symptoms as either T1D or T2D patients. Currently, there is little understanding of CFRD and the best options for treatment remain unclear. The purpose of this research study is to examine and understand the various mechanisms that contribute to CFRD and gain a better understanding of potential means to treat CFRD. In particular, we plan to study the effects of incretin hormones that can enhance insulin production in CF patients. Enrollment is complete for the protocol as initially written. In order to further study the role of the incretin hormone on Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) function , we have received approval to extend our investigation to include the following study groups: * Cystic Fibrosis participants with normal glucose tolerance * Non-Cystic Fibrosis controls
• Confirmed diagnosis of cystic fibrosis, defined by positive sweat test or CFTR mutation analysis according to CFF diagnostic criteria,
• Age greater than or equal to 18y on date of consent
• Pancreatic insufficiency
• Recent OGTT consistent with Indeterminate-GT, IGT, CFRD w/o fasting hyperglycemia, or an established diagnosis of CFRD without fasting hyperglycemia
• For female subjects, negative urine pregnancy test at enrollment.
⁃ Control Subjects:
• No history of cystic fibrosis.
• Age ≥ 18y on date of consent.
• Recent OGTT consistent with NGT.
• For female subjects, negative urine pregnancy test at enrollment.