Stimulated Glucagon As a Biomarker of Hypoglycemic Risk in Type 1 Diabetes

At either Visit 1 or Visit 2, participants will be given Ensure HP or Fortisip (a drink containing the same amounts of carbohydrates, protein and fats as there would be in a meal; 6ml/kg to a max of 360mls), and have blood samples collected, to measure insulin (C-peptide), glucose, and glucagon, at specific intervals: -10, 0, 30, 60, 90, 120 minutes post meal. This test is used to measure how a participant's beta cells are working to produce insulin after a meal and to check for reactive hypoglycaemia.

At either Visit 1 or Visit 2, and Visit 3, participants will be given a dose of Arginine Hydrochloride (5 g Arginine during 1 min) by intravenous injection, and have blood samples collected to measure insulin (C-peptide), glucose, and glucagon, at specific intervals: -10, 0, 2, 5, 10, 15 and 30 minutes following the Arginine bolus injection. This test is designed primarily to test the maximum insulin secretion capacity of a participant's beta cells.

Participants will be provided with a kit to collect an optional home finger prick sample the day after each visit, and return the sample using the prepaid addressed padded envelope provided.