Epidermal growth factor and haptocorrin in nasal secretion

Abstract

We report that nasal secretion contains the growth-promoting peptide epidermal growth factor (EGF) and a cobalamin-binding protein. Based on its amino-terminal sequence the cobalamin binding protein is classified as haptocorrin (HC). We have investigated the concentration of these components, the volume secreted, and the concentration of total protein after nasal challenge with methacholine, methacholine + ephedrine, histamine and serotonin. The EGF and HC concentrations do not differ for the four challenge agents employed. Range and median for all values obtained are 0.1-2.5 (0.7) nmol/1 (n=49) for EGF and 50-405 (190) nmol/1 (n=63) for HC. After challenge with methacholine the amount of secretion (80-630 (200) mg (n=14)) and the protein concentration (1.5-7.8 (3.5) g/1 (n=14)) are lower than for any other challenge. After challenge with serotonin or histamine the amount secreted is 60-1125 (480) mg (n=39). The concentration of protein is significantly higher (p<0.01) after challenge with serotonin (1.4-56.0 (17.0) g/1 (n=18)) than after challenge with histamine (2.0-25.0 (5.0) g/1 (n=20)).

Key Words:

• cobalamin
• cobalamin-binding proteins
• ephedrine
• histamine
• methacholine
• serotonin