Intrapulmonary administration of insulin to healthy volunteers.
OBJECTIVE
To study the biological effects of nebulized insulin, administered intrapulmonary, to healthy volunteers.


METHODS
A double-blind, randomized, controlled intervention study.


METHODS
The department of Internal Medicine, University Hospital, Linköping, Sweden.


METHODS
Eight healthy, non-smoking volunteers, with a mean age of 28 (range 22 to 56) years.


METHODS
Regular human insulin 100 U mL-1 (Actrapid) or 0.9% saline was given randomly as an oral inhalation. Insulin was given in three different doses (40, 80 and 160 U). Aerosol was generated by a new jet nebulizer.


METHODS
Blood glucose, serum insulin, and serum C-peptide.


RESULTS
After the 160 U insulin dose the blood glucose concentration (mean +/- SE) fell from 4.3 +/- 0.2 to 2.8 +/- 0.2 mmol L-1 (P < 0.001), concomitant with an increase in mean serum insulin concentrations, rising from 9.5 +/- 1.5 to 26.1 +/- 2.5 mU L-1 (P < 0.001). Serum C-peptide concentrations simultaneously decreased from 0.48 +/- 0.03 to 0.12 +/- 0.02 mmol L-1 (P < 0.001). All changes were dose dependent. No adverse reactions were noted and no significant changes in lung function tests.


CONCLUSIONS
Intrapulmonary insulin administration to healthy subjects can induce a significant hypoglycaemia and cause a clinically relevant increase in serum insulin concentrations. If similar results can be obtained when administering insulin to diabetic subjects, this insulin administration route can be a future complement to certain groups of patients.
Jendle
J H
JH
Department of Internal Medicine, Faculty of Health Sciences, Linköping University, Sweden.
Karlberg
B E
BE
D000280:Administration, Inhalation; D000328:Adult; D000336:Aerosols; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000097:blood; D004311:Double-Blind Method; D006801:Humans; D007328:Insulin / Q000008:administration & dosage* / Q000097:blood; D008875:Middle Aged; D012016:Reference Values
D000336:Aerosols; D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin