Day 1. Baseline assessment. The participant will attend after an overnight fast at 0830 for frequently sampled intravenous glucose tolerance test (FSIGT). Two IV lines will be placed and baseline blood samples (30ml) are drawn for measurement of gluco-regulatory hormones and metabolites at time 0. A glucose bolus is then administered through the antecubital vein IV (300mg/kg, 25% Dextrose infused over 1-minute) at time 0. Blood sampling (3ml) is then performed at 2,4,6,8,10,12,14,16,19,22,25,30,40,50,60,70,90,120,150,180 minutes after the completion of the glucose bolus. Each blood sample is analysed for glucose and insulin. Total blood collected during this procedure is approximately 60mls. A urine sample will be collected. A meal will be provided.