Dose-Finding Study of Intranasal Insulin in Healthy Participants Insulin in Healthy Participants

"This will be given intranasally at differing doses depending on study day. A total of 11 possible doses will be tested, ranging from 0 to 1000 U insulin. Each volunteer will come for 5 visits.~On the first treatment day participants will receive placebo (sterile water) in each nostril followed by a 4-hour observation period. After this observation period participants will receive the initial dose of insulin squirted in each nostril followed by a a 4 hour observation period. Participants will have at least 7 days in between the other 4 visits. Subsequent visits will include increased doses of insulin (depending on how this is tolerated) and will take approximately 4 hours at these visits."