Role of Glucagon In Glucose Control in Cystic Fibrosis Related Diabetes
Condition: Cystic Fibrosis; Cystic Fibrosis Related Diabetes
MeSH terms: Cystic Fibrosis; Diabetes Mellitus; Fibrosis
Study type: Interventional
Phase: Early Phase 1

Summary: 
      This project is designed to begin to characterize the abnormalities of glucagon secretion in
      subjects with cystic fibrosis related diabetes along the spectrum of glucose tolerance.
      Cystic fibrosis patients with normal glucose tolerance as well as cystic fibrosis related
      diabetes as well as control subjects will undergo an oral glucose tolerance test, mixed meal
      tolerance test, and one step hypoglycemic clamp. Cystic fibrosis patients will then return 12
      months later to undergo repeat mixed meal tolerance test and hypoglycemic clamp test.
    

Detailed description: 
      This project is designed to begin to characterize the abnormalities of glucagon secretion in
      subjects with cystic fibrosis related diabetes along the spectrum of glucose tolerance. This
      will be a descriptive, cross-sectional and longitudinal cohort study in a sample of children
      and young adults with CF and a continuum of glucose tolerance compared to healthy age-matched
      controls.

      Cystic fibrosis patients with normal glucose tolerance as well as cystic fibrosis related
      diabetes as well as control subjects will be admitted to the research unit on three separate
      occasions to undergo an oral glucose tolerance test, mixed meal tolerance test, and one step
      hypoglycemic clamp. Cystic fibrosis patients will then return 12 months later to undergo
      repeat mixed meal tolerance test and hypoglycemic clamp test.
    

Intervention name(s): Oral Glucose Tolerance Test; Mixed Meal Tolerance Test; Hypoglycemic Clamp
Intervention type(s): Other; Other; Other
Intervention description(s): Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling. Patients will drink 1.75 gm/kg glucose (Glucola) to a maximum of 75 gm. Venous samples for glucose and c-peptide will be drawn from the IV at 0, 30, 60, 90 and 120 minutes. Subjects will be instructed to eat at least 75 gm carbohydrates daily in the week prior to this test.; Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling. Subjects will consume 6 kcal/kg (6 ml/kg) Boost High Protein Nutritional Energy Drink (Mead-Johnson) over five minutes to a maximum of 360 ml. Venous samples for glucose, glucagon, GLP-1, GIP, and c-peptide will be drawn at -10, 0, 15, 30, 60, 90, 120, 150, 180, 210, and 240 minutes.; All subjects with CF and adult (but not pediatric) controls will undergo one-step hypoglycemic clamp. Subjects will be instructed to fast after midnight the night prior to the study. Subjects will be admitted to the research unit on the morning of the test for placement of blood-drawing IV for frequent sampling and a second IV for infusion of insulin and dextrose.
Intervention MeSH terms: Hypoglycemic Agents
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science