Intranasal Insulin and Its Effect on Postprandial Glucose Metabolism in Comparison to Subcutaneous Insulin

Diabetes mellitus is a common metabolic disorder characterized by hyperglycemia which when untreated is associated with microvascular disease. Most people with type 1 diabetes are treated with a combination of long-acting (basal) insulin and short-acting (prandial) insulin administered prior to meals. This necessitates multiple daily injections (>3) which is a significant barrier to long-term compliance and treatment. Intranasal administration of insulin has been developed in an effort to overcome the need for insulin injection prior to meals. The pharmacokinetic properties conferred to insulin by this route of administration suggest that postprandial glucose disposal may be stimulated leading to lower glucose concentrations in comparison to dosing via other routes. We propose to study postprandial glucose turnover in healthy volunteers with Type 1 diabetes to determine the effect of intranasal insulin on glucose disposal. We wish to do so in order to develop a greater understanding of how the different bioavailability timing of intranasal insulin might alter postprandial glucose disposal and suppression of endogenous glucose production. In order to address these questions we will address specific aims:

• Peak postprandial glucose disposal is higher and occurs earlier, in the presence of intranasal insulin administration than it is in more conventional forms of insulin dosing.
• Peak suppression of endogenous glucose production is greater and occurs earlier, in the presence of intranasal insulin administration than it is in more conventional forms of insulin dosing.