Insulin administration and rate of glucose appearance in people with type 1 diabetes

OBJECTIVE — To assess whether prandial insulin, in addition to basal insulin, has an effect on the rate of glucose appearance from a meal in people with type 1 diabetes. RESEARCHDESIGNANDMETHODS — The rate of glucose appearance from a mixed meal (Rameal) was investigated in six adult (aged 24 2 years), lean (BMI 23.6 1.5 kg/m 2) subjects with well-controlled type 1 diabetes (duration 7.9 6.9 years, A1C 7.6 0.9%) with/without prandial insulin. Actrapid was infused to maintain euglycemia before meals were consumed. Subjects consumed two identical meals on separate occasions, and Rameal was mea-sured using a dual isotope method. [6,6-2H2]glucose was incorporated into the meal (0.081 g/kg body wt), and a primed constant/variable rate infusion of [1,2,3,4,5,6,6-2H2]glucose was ad-ministered. In the tests with prandial insulin, an additional bolus dose of Actrapid was given 20 min before the meal at 0.1 units/kg body wt. RESULTS — Insulin concentration with prandial insulin was significantly higher than during basal insulin studies (119 16 vs. 66 15 pmol/l, P 0.03 by paired t test). Despite differences in insulin concentration, there were no differences in total glucose appearance (3,398 197 vs