The intra-nasal administration of insulin induces significant hypoglycaemia and classical counterregulatory hormonal responses in normal man.

The present study aimed at investigating the metabolic and hormonal consequences of intra-nasal administration of insulin in normal man. Lyophylisated regular porcine insulin (Insuline Ordinaire Organon) diluted with a non ionic detergent (Laureth-9 0,25%) was administered intra-nasally in 8 overnight fasted healthy volunteers using a calibrated aerosol delivery device (90 microliters = 9 U of insulin/spray) up to a total insulin dose close to 1 U/kg body weight. After intra-nasal insulin administration, plasma insulin levels rose from 5 +/- 1 to 38 +/- 10 mU/l (2p less than 0.01) at min 15, blood glucose concentrations decreased from 4.4 +/- 0.2 to 3.2 +/- 0.3 mmol/l (2p less than 0.01) at min 45, plasma C-peptide levels diminished from 327 +/- 31 to 174 +/- 28 mumol/l (2p less than 0.01) at min 60 and plasma free fatty acids concentrations fell from 336 +/- 109 to 130 +/- 31 mumol/l (2p less than 0.05) at min 30. The fall in blood glucose resulted in a prompt increase in plasma glucagon levels (from 78 +/- 28 to 150 +/- 24 ng/l at min 45; 2p less than 0.05) and in later rises in plasma growth hormone and cortisol concentrations. There was a close relationship between the individual maximal decreases in blood glucose levels and the individual maximal increases in plasma insulin (r = 0.81), glucagon (r = 0.88), cortisol (r = 0.87) and growth hormone (r = 0.76) concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)