Regulation of Endogenous Glucose Production by Brain Insulin Action — Nasal insulin  

Insulin Resistance, Diabetes Clinical Trial

Official title: Regulation of Endogenous Glucose Production by Brain Insulin Action

Status Completed

Clinical Trial Summary

It is well known that the hormone insulin lowers blood glucose in part by acting directly on the liver and reducing hepatic glucose production. Animal studies have shown that the hormone insulin can act on the brain to indirectly lower glucose production by the liver. We aim to test whether this is true in humans by giving insulin intranasally. It has previously been shown that a nasal spray can deliver insulin directly to the brain without affecting circulating insulin concentration.

Clinical Trial Description

Each study participant will be admitted to hospital the evening prior to the study. Following admission each study participant will be provided with a standardized dinner. At 7am (t=0) the next day we will begin a primed, constant intravenous infusion d2 glucose (a stable isotope of glucose, the enrichment of which can be measured by gas chromatography mass spectrometry, allowing us to calculate endogenous glucose production rates) and continue this for 8 hours. At the same time (7am) a pancreatic clamp will be started as described above for 8 hours. Blood samples will be analysed with a glucometer for instant blood glucose readings At 9 am (+120 minutes) intranasal placebo or insulin will be administered. The insulin (Humalog Lispro 100 IU/ml, Eli Lily, Canada) and placebo (diluent) will be transferred to a metered nasal device (Pharmasystems, Ontario UPC: 063636 802721, Item 10271) immediately prior to use. This device dispenses 0.1ml (10 IU) per puff. 4X0.1 ml puffs/vials (2 per nostril) will be administered at rate of 2 (one in each nostril) every 60 seconds. Blood will be drawn at t=0, 30, 60, 120 and every 10 minutes thereafter for 6 hours. In order to match peripheral lispro concentrations between study visits, a small dose of Humalog (lispro) insulin will be administered intravenously at 9am, during the placebo arm of the study. Based on the pharmacokinetics of Humalog lispro (personal communication from Eli Lilly), we propose to administer 0.005 IU/kg over 30 minutes. 20% dextrose will be administered to maintain euglycemia as necessary. Insulin, glucagon, and glucose isotopic enrichment will be measured. The enrichment data and glucose infusion will be used to calculate steady state glucose production. ;

Study Design

Allocation: Randomized, Intervention Model: Crossover Assignment, Masking: Single Blind (Subject), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Insulin Resistance
• Insulin Resistance, Diabetes

• NCT number: NCT02131948
• Study type: Interventional
• Source: University Health Network, Toronto
• Status: Completed
• Phase: Phase 1
• Start date: November 2013
• Completion date: July 2014