Intrapulmonary administration of insulin to healthy volunteers

J Intern Med. 1996 Aug;240(2):93-8. doi: 10.1046/j.1365-2796.1996.502836000.x.


Objectives: To study the biological effects of nebulized insulin, administered intrapulmonary, to healthy volunteers.

Design: A double-blind, randomized, controlled intervention study.

Setting: The department of Internal Medicine, University Hospital, Linköping, Sweden.

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

Interventions: 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.

Main outcome measures: 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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Administration, Inhalation
  • Adult
  • Aerosols
  • Blood Glucose / metabolism
  • C-Peptide / blood
  • Double-Blind Method
  • Humans
  • Insulin / administration & dosage*
  • Insulin / blood
  • Middle Aged
  • Reference Values


  • Aerosols
  • Blood Glucose
  • C-Peptide
  • Insulin