Effect of inhaled 15-(s)-hydroxyeicosatetraenoic acid on tracheobronchial clearance in normal human airways.

15-(s)-Hydroxyeicosatetraenoic acid (15-HETE) is the predominant metabolite of arachidonic acid in normal and asthmatic human airways and a potent mucus secretagogue in canine and human airways. A study was carried out on the effect of inhaled 15-HETE on tracheobronchial clearance, measured for six hours by a radioaerosol technique, in 10 normal subjects. Subjects inhaled 80 nmol 15-HETE or the diluent (sodium phosphate buffer) on two occasions at least two weeks apart in a double blind and randomised fashion (20 minutes after radioaerosol inhalation. Tracheobronchial clearance after inhaled 15-HETE was almost identical to that after placebo for all measurements up to six hours. It is concluded that 15-HETE has no effect on tracheobronchial clearance in normal human airways and is unlikely to account for the impaired mucociliary clearance seen in asthma.